Method and apparatus for transmitting DMRS

ABSTRACT

Embodiments of this application disclose a method and an apparatus for transmitting a DMRS, and relate to the field of communications technologies. The method and the apparatus are applicable to an NR system. The method for transmitting a DMRS may include: determining a time-frequency resource used to carry a DMRS; and then sending the DMRS by using the time-frequency resource.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/566,362, filed on Sep. 10, 2019, which is a continuation ofInternational Application No. PCT/CN2018/080723, filed on Mar. 27, 2018.The International Application claims priority to Chinese PatentApplication No. 201710214876.X, filed on Apr. 1, 2017. All of theafore-mentioned patent applications are hereby incorporated by referencein their entireties.

TECHNICAL FIELD

Embodiments of this application relate to the field of communicationstechnologies, and in particular, to a method and an apparatus fortransmitting a demodulation reference signal (DMRS).

BACKGROUND

In an existing long term evolution (LTE) standard, single user (SU)multiple-input multiple-output (MIMO) supports multiplexing for amaximum of eight layers of orthogonal DMRS ports, and a DMRS occupies 24REs. Specifically, the DMRS ports may be mapped to a subcarrier 0, asubcarrier 1, a subcarrier 5, a subcarrier 6, a subcarrier 10, and asubcarrier 11 of each resource block (RB) pair in frequency domain, andthe DMRS ports may be mapped to a symbol 5, a symbol 6, a symbol 12, anda symbol 13 of each subframe in a time domain, as shown in FIG. 1 .

The foregoing technical solution is not applicable to a new radio (NR)system. For example, a DMRS in LTE is placed in the middle or rear ofeach subframe. A receive end needs to receive all DMRSs beforeperforming data demodulation. Consequently, a requirement for rapid datademodulation in NR cannot be satisfied.

SUMMARY

This application provides a method and an apparatus for transmitting aDMRS, which are applicable to an NR system.

According to a first aspect, this application provides a method and anapparatus for determining a time-frequency resource used to carry aDMRS.

In a possible design, the method may include: determining atime-frequency resource used to carry a DMRS. For a related descriptionof the time-frequency resource, refer to the following descriptions.

Correspondingly, this application further provides the apparatus fordetermining a time-frequency resource used to carry a DMRS. Theapparatus may implement the method for determining a time-frequencyresource used to carry a DMRS. For example, the apparatus may be a chip(for example, a baseband chip or a communications chip) or a transmitend (for example, a base station or a terminal). The apparatus mayimplement the foregoing method by using software or hardware or by usinghardware by executing corresponding software.

In a possible design, the apparatus may include a processor and amemory. The processor is configured to support the apparatus inperforming corresponding functions in the foregoing method fordetermining a time-frequency resource used to carry a DMRS. The memoryis configured to be coupled to the processor, and store a program (aninstruction) and data that are necessary for the apparatus. Optionally,the apparatus may further include a communications interface, configuredto support communication between the apparatus and another networkelement. The communications interface may be a transceiver.

In another possible design, the apparatus may include: a determiningunit, configured to determine a time-frequency resource used to carry aDMRS. For a related description of the time-frequency resource, refer tothe following descriptions.

According to a second aspect, this application provides a method and anapparatus for sending a DMRS.

In a possible design, the method may include: determining atime-frequency resource used to carry a DMRS; and then sending the DMRSby using the time-frequency resource, that is, determining thetime-frequency resource used to carry the DMRS, and then sending theDMRS by using the determined time-frequency resource.

In a possible design, the DMRS is carried in at least one resource unit;and if a total quantity of system-supported DMRS ports is 6, in eachresource unit, a time-frequency resource occupied by the DMRS includes afirst symbol in time domain, and includes any one of the followingsubcarriers in frequency domain: a subcarrier 6n, a subcarrier 6n+1, asubcarrier 6n+2, a subcarrier 6n+3, a subcarrier 6n+4, and a subcarrier6n+5, where n may be any one or more integers greater than or equal to 0and less than └M/6┘. For a specific example and a related descriptionthereof, refer to (a) in FIG. 7 . It can be understood that the “DMRS”herein is a reference signal; the “time-frequency resource used to carrya DMRS” may be understood as an RE that is in one or more resource unitsand that is used to carry the DMRS; and the “time-frequency resourceoccupied by the DMRS in each resource unit” is an RE that is in oneresource unit and that is used to carry the DMRS. These terms in thefollowing examples have similar meanings as those described above, andtherefore details are not described.

In a possible design, the DMRS is carried in at least one resource unit;and if a total quantity of system-supported DMRS ports is 6, the sixDMRS ports are divided into three DMRS port groups, and a sametime-frequency resource is multiplexed for DMRS ports in each DMRS portgroup in a CDM manner, in each resource unit, a time-frequency resourceoccupied by the DMRS includes a first symbol in time domain, andincludes any one of the following subcarriers in frequency domain: asubcarrier 3n, a subcarrier 3n+1, and a subcarrier 3n+2, where

n may be any one or more integers greater than or equal to 0 and lessthan └M/3┘; and for a specific example and a related descriptionthereof, reference may be made to (a) in FIG. 8 .

In a possible design, the DMRS is carried in at least one resource unit;and if a total quantity of system-supported DMRS ports is 6, in eachresource unit, a time-frequency resource occupied by the DMRS has anyone of the following features:

when the time-frequency resource occupied by the DMRS is a first symbolin time domain, the time-frequency resource includes a subcarrier 6n ofthe resource unit in frequency domain; and when the time-frequencyresource occupied by the DMRS is a second symbol in time domain, thetime-frequency resource includes a subcarrier 6n+3 of the resource unitin frequency domain;

when the time-frequency resource occupied by the DMRS is a first symbolin time domain, the time-frequency resource includes a subcarrier 6n+1of the resource unit in frequency domain; and when the time-frequencyresource occupied by the DMRS is a second symbol in time domain, thetime-frequency resource includes a subcarrier 6n+4 of the resource unitin frequency domain;

when the time-frequency resource occupied by the DMRS is a first symbolin time domain, the time-frequency resource includes a subcarrier 6n+2of the resource unit in frequency domain; and when the time-frequencyresource occupied by the DMRS is a second symbol in time domain, thetime-frequency resource includes a subcarrier 6n+5 of the resource unitin frequency domain;

when the time-frequency resource occupied by the DMRS is a first symbolin time domain, the time-frequency resource includes a subcarrier 6n+3of the resource unit in frequency domain; and when the time-frequencyresource occupied by the DMRS is a second symbol in time domain, thetime-frequency resource includes a subcarrier 6n of the resource unit infrequency domain;

when the time-frequency resource occupied by the DMRS is a first symbolin time domain, the time-frequency resource includes a subcarrier 6n+4of the resource unit in frequency domain; and when the time-frequencyresource occupied by the DMRS is a second symbol in time domain, thetime-frequency resource includes a subcarrier 6n+1 of the resource unitin frequency domain; or

when the time-frequency resource occupied by the DMRS is a first symbolin time domain, the time-frequency resource includes a subcarrier 6n+5of the resource unit in frequency domain; and when the time-frequencyresource occupied by the DMRS is a second symbol in time domain, thetime-frequency resource includes a subcarrier 6n+2 of the resource unitin frequency domain, where

n may be any one or more integers greater than or equal to 0 and lessthan └M/6┘; and for a specific example and a related descriptionthereof, reference may be made to (c) in FIG. 11 .

In a possible design, the DMRS is carried in at least one resource unit;and if a total quantity of system-supported DMRS ports is 6, the sixDMRS ports are divided into three DMRS port groups, and a sametime-frequency resource is multiplexed for DMRS ports in each DMRS portgroup in a CDM manner, in each resource unit, a time-frequency resourceoccupied by the DMRS has any one of the following features:

when the time-frequency resource occupied by the DMRS is a first symbolin time domain, the time-frequency resource includes a subcarrier 3n ofthe resource unit in frequency domain; and when the time-frequencyresource occupied by the DMRS is a second symbol in time domain, thetime-frequency resource includes a subcarrier 3n+2 of the resource unitin frequency domain;

when the time-frequency resource occupied by the DMRS is a first symbolin time domain, the time-frequency resource includes a subcarrier 3n+1of the resource unit in frequency domain; and when the time-frequencyresource occupied by the DMRS is a second symbol in time domain, thetime-frequency resource includes a subcarrier 3n of the resource unit infrequency domain; or

when the time-frequency resource occupied by the DMRS is a first symbolin time domain, the time-frequency resource includes a subcarrier 3n+2of the resource unit in frequency domain; and when the time-frequencyresource occupied by the DMRS is a second symbol in time domain, thetime-frequency resource includes a subcarrier 3n+1 of the resource unitin frequency domain, where

n may be any one or more integers greater than or equal to 0 and lessthan └M/3┘; and for a specific example and a related descriptionthereof, reference may be made to (c) in FIG. 12 .

It can be understood that the foregoing lists features of atime-frequency resource occupied by one DMRS in different situations.During specific implementation, for features in other examples in thefollowing, refer to features of a time-frequency resource occupied byone DMRS in other situations in the foregoing manner, and features oftime-frequency resources occupied by a plurality of DMRSs may beinferred based on the features. Details are not described herein.

Correspondingly, this application further provides the apparatus forsending a DMRS. The apparatus may implement the method for sending aDMRS according to the second aspect. For example, the apparatus may be atransmit end (for example, a base station or a terminal), and mayimplement the foregoing method by using software or hardware or by usinghardware by executing corresponding software.

In a possible design, the apparatus may include a processor and amemory. The processor is configured to support the apparatus inperforming corresponding functions in the method according to the secondaspect. The memory is configured to be coupled to the processor, andstore a program (an instruction) and data that are necessary for theapparatus. Optionally, the apparatus may further include acommunications interface, configured to support communication betweenthe apparatus and another network element. The communications interfacemay be a transceiver.

In another possible design, the apparatus may include a determining unitand a sending unit. The determining unit is configured to determine atime-frequency resource used to carry a DMRS. The sending unit isconfigured to send the DMRS by using the time-frequency resource.

According to a third aspect, this application provides a method and anapparatus for obtaining a DMRS.

In a possible design, the method may include: determining atime-frequency resource used to carry a DMRS; and then obtaining theDMRS by using the time-frequency resource.

Correspondingly, this application further provides the apparatus forobtaining a DMRS. The apparatus may implement the method for obtaining aDMRS according to the third aspect. For example, the apparatus may be areceive end (for example, a base station or a terminal), and mayimplement the foregoing method by using software or hardware or by usinghardware by executing corresponding software.

In a possible design, the apparatus may include a processor and amemory. The processor is configured to support the apparatus inperforming corresponding functions in the method according to the thirdaspect. The memory is configured to be coupled to the processor, andstore a program (an instruction) and data that are necessary for theapparatus. Optionally, the apparatus may further include acommunications interface, configured to support communication betweenthe apparatus and another network element. The communications interfacemay be a transceiver.

In another possible design, the apparatus may include a determining unitand an obtaining unit. The determining unit may be configured todetermine a time-frequency resource used to carry a DMRS. The obtainingunit may be configured to obtain the DMRS by using the time-frequencyresource.

According to a fourth aspect, this application provides an indicationmethod and apparatus.

In a possible design, the method may include: generating indicationinformation, where the indication information is used to indicate atime-frequency resource used to carry a DMRS; and then sending theindication information. The method may be performed by a base station.Optionally, the indication information may be information used toindicate a pilot pattern, for example, an index of a pilot pattern, andis used to instruct a terminal to determine a pilot pattern used by thebase station in a current scheduling process. This optionalimplementation is applicable to a scenario in which a plurality of pilotpatterns may be used during communication between the base station andthe terminal. Optionally, the indication information may be informationused to indicate a DMRS port, for example, a DMRS port identifier (forexample, a DMRS port number), and is used to instruct a terminal todetermine a DMRS port allocated by the base station to the terminal in acurrent scheduling process. This optional implementation is applicableto a scenario in which one or more pilot patterns may be used duringcommunication between the base station and the terminal.

Correspondingly, this application further provides the apparatus forsending a DMRS. The apparatus may implement the indication methodaccording to the fourth aspect. For example, the apparatus may be a basestation, and may implement the foregoing method by using software orhardware or by using hardware by executing corresponding software.

In a possible design, the apparatus may include a processor and amemory. The processor is configured to support the apparatus inperforming corresponding functions in the method according to the fourthaspect. The memory is configured to be coupled to the processor, andstore a program (an instruction) and data that are necessary for theapparatus. Optionally, the apparatus may further include acommunications interface, configured to support communication betweenthe apparatus and another network element. The communications interfacemay be a transceiver.

In another possible design, the apparatus may include a generation unitand a sending unit. The generation unit is configured to generateindication information, where the indication information is used toindicate a time-frequency resource used to carry a DMRS. The sendingunit is configured to send the indication information.

According to a fifth aspect, this application provides a method and anapparatus for determining a time-frequency resource.

In a possible design, the method may include: receiving indicationinformation, where the indication information is used to indicate atime-frequency resource used to carry a DMRS; and then determining,based on the indication information, the time-frequency resource used tocarry the DMRS.

Correspondingly, this application further provides the apparatus forobtaining a DMRS. The apparatus may implement the method for determininga time-frequency resource according to the fifth aspect. For example,the apparatus may be a terminal, and may implement the foregoing methodby using software or hardware or by using hardware by executingcorresponding software.

In a possible design, the apparatus may include a processor and amemory. The processor is configured to support the apparatus inperforming corresponding functions in the method according to the fifthaspect. The memory is configured to be coupled to the processor, andstore a program (an instruction) and data that are necessary for theapparatus. In addition, the apparatus may further include acommunications interface, configured to support communication betweenthe apparatus and another network element. The communications interfacemay be a transceiver.

In another possible design, the apparatus may include a receiving unitand a determining unit. The receiving unit is configured to receiveindication information, where the indication information is used toindicate a time-frequency resource used to carry a DMRS. The determiningunit is configured to determine, based on the indication information,the time-frequency resource used to carry the DMRS.

This application further provides a computer storage medium. Thecomputer storage medium stores a computer program (an instruction). Whenthe program (instruction) runs on a computer, the computer performs themethod according to any one of the foregoing aspects.

This application further provides a computer program product. When thecomputer program product runs on a computer, the computer performs themethod according to any one of the foregoing aspects.

The foregoing provided time-frequency resource used to carry the DMRShas a mapping relationship with the DMRS port. Therefore, thisapplication further provides several mapping rules between a DMRS portand a time-frequency resource. For a detailed description of each ruleand analysis of a beneficial effect of the rule, refer to the followingspecific implementations. Details are not described herein.

It can be understood that any one of the foregoing provided apparatuses,computer storage medium, or computer program product is configured toperform the foregoing provided corresponding method. A beneficial effectthat can be achieved by using the foregoing provided method is relatedto the mapping relationship between a time-frequency resource used tocarry a DMRS and a DMRS port. Therefore, for a beneficial effect thatcan be achieved by the apparatuses, computer storage medium, or computerprogram product, refer to a beneficial effect of a correspondingsolution in the following specific implementations. Details are notdescribed herein.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic diagram of a pilot pattern according to the priorart;

FIG. 2 is a schematic diagram of a resource unit according to anembodiment of this application;

FIG. 3 is a schematic diagram of a system architecture to which atechnical solution is applied according to an embodiment of thisapplication;

FIG. 4 is a schematic structural diagram of a base station according toan embodiment of this application;

FIG. 5 is a schematic structural diagram of a terminal according to anembodiment of this application;

FIG. 6 is a schematic interaction diagram of a method for transmitting aDMRS according to an embodiment of this application;

FIG. 6 a is a schematic interaction diagram of another method fortransmitting a DMRS according to an embodiment of this application;

FIG. 7 is a schematic diagram of a pilot pattern for six ports accordingto an embodiment of this application;

FIG. 8 is a schematic diagram of another pilot pattern for six portsaccording to an embodiment of this application;

FIG. 9 is a schematic diagram of another pilot pattern for six portsaccording to an embodiment of this application;

FIG. 10 is a schematic diagram of another pilot pattern for six portsaccording to an embodiment of this application;

FIG. 11 is a schematic diagram of another pilot pattern for six portsaccording to an embodiment of this application;

FIG. 12 is a schematic diagram of another pilot pattern for six portsaccording to an embodiment of this application;

FIG. 13 is a schematic diagram of another pilot pattern for six portsaccording to an embodiment of this application;

FIG. 14 is a schematic diagram of another pilot pattern for six portsaccording to an embodiment of this application;

FIG. 15 is a schematic diagram of a pilot pattern for eight portsaccording to an embodiment of this application;

FIG. 16 is a schematic diagram of another pilot pattern for eight portsaccording to an embodiment of this application;

FIG. 17 is a schematic diagram of another pilot pattern for eight portsaccording to an embodiment of this application;

FIG. 18 is a schematic diagram of another pilot pattern for eight portsaccording to an embodiment of this application;

FIG. 19 is a schematic diagram of a pilot pattern for 12 ports accordingto an embodiment of this application;

FIG. 20 is a schematic diagram of another pilot pattern for 12 portsaccording to an embodiment of this application;

FIG. 21 is a schematic diagram of another pilot pattern for 12 portsaccording to an embodiment of this application;

FIG. 22 is a schematic diagram of another pilot pattern for 12 portsaccording to an embodiment of this application;

FIG. 23 is a schematic diagram of another pilot pattern for 12 portsaccording to an embodiment of this application;

FIG. 24 is a schematic diagram of another pilot pattern for 12 portsaccording to an embodiment of this application;

FIG. 25 is a schematic diagram of another pilot pattern for 12 portsaccording to an embodiment of this application;

FIG. 26 is a schematic diagram of another pilot pattern for 12 portsaccording to an embodiment of this application;

FIG. 27 is a schematic diagram of another pilot pattern for 12 portsaccording to an embodiment of this application;

FIG. 28 is a schematic diagram of another pilot pattern for 12 portsaccording to an embodiment of this application;

FIG. 29 is a schematic diagram of a pilot pattern for 16 ports accordingto an embodiment of this application;

FIG. 30 is a schematic diagram of another pilot pattern for 16 portsaccording to an embodiment of this application;

FIG. 31 is a schematic diagram of another pilot pattern for 16 portsaccording to an embodiment of this application;

FIG. 32 is a schematic diagram of another pilot pattern for 16 portsaccording to an embodiment of this application;

FIG. 33 is a schematic diagram of another pilot pattern for 16 portsaccording to an embodiment of this application;

FIG. 34 is a schematic diagram of another pilot pattern for 16 portsaccording to an embodiment of this application;

FIG. 35 is a schematic structural diagram of an apparatus for sending aDMRS according to an embodiment of this application;

FIG. 36 is a schematic structural diagram of an apparatus for obtaininga DMRS according to an embodiment of this application;

FIG. 37 is a schematic structural diagram of an indication apparatusaccording to an embodiment of this application;

FIG. 38 is a schematic structural diagram of an apparatus fordetermining a time-frequency resource according to an embodiment of thisapplication; and

FIG. 39 is a schematic structural diagram of an apparatus fortransmitting a DMRS according to an embodiment of this application.

DESCRIPTION OF EMBODIMENTS

First, terms related to this specification are briefly described to helpa reader have a better understanding.

(1) Resource Unit

Similar to an RB and an RB pair in the LTE standard, a resource unit isprovided in some embodiments of this application. The resource unit maybe used as a basic unit for scheduling a terminal to perform resourceallocation, or may be used to describe an arrangement manner of aplurality of reference signals.

The resource unit may include a plurality of consecutive subcarriers infrequency domain and one time interval (TI) in time domain. In differentscheduling processes, sizes of resource units may be the same ordifferent. The TI herein may be a transmission time interval (TTI) in anLTE system, a symbol-level short TTI, a short TTI of a large subcarrierspacing in a high-frequency system, a slot or a mini-slot in a 5Gsystem, or the like. This is not limited in this application.

Optionally, one resource unit may include one or more RBs, one or moreRB pairs, or the like, or may be half an RB or the like. Alternatively,one resource unit may be another time-frequency resource. This is notlimited in this application. One RB pair includes 12 consecutivesubcarriers in frequency domain and one subframe in time domain. Atime-frequency resource that includes one subcarrier in frequency domainand one symbol in time domain is a resource element (RE), as shown inFIG. 2 . An RB pair in FIG. 2 includes 12 consecutive subcarriers(numbered from 0 to 11) in frequency domain and 14 symbols (numberedfrom 0 to 13) in time domain. In FIG. 2 , a horizontal coordinate axisindicates a time domain and vertical coordinate axis indicates frequencydomain. It should be noted that the accompanying drawings that areincluded in this application and that indicate a time-frequency domainresource are described by using the RB pair shown in FIG. 2 as anexample. A person skilled in the art may understand that this is notlimited during specific implementation. It can be understood that a“symbol” in this application may include, but is not limited to, any oneof the following: an orthogonal frequency division multiplexing (OFDM)symbol, a universal filtered multi-carrier (UFMC) signal, a filter bankmulti-carrier (FBMC) symbol, a generalized frequency-divisionmultiplexing (GFDM) symbol, and the like.

(2) DMRS Port Group

A “DMRS port group” in this application is a logical concept introducedto clearly describe the technical solutions provided in thisapplication, and specifically, is a logical concept introduced toclearly describe a pilot pattern or a variation of the pilot patternprovided in this application. It can be understood that during actualimplementation, a base station and a terminal may not perform an actionof grouping DMRS ports. Any manner used to design the pilot pattern orthe variation of the pilot pattern described in this application shallfall within the protection scope of this application.

One DMRS port group may include one or more DMRS ports. In thisapplication, a same time-frequency resource is multiplexed for DMRSscorresponding to ports in a DMRS port group in a (code divisionmultiplexing (CDM) manner, for example, by using a method such asorthogonal cover code (OCC), cyclic shift (CS), or cyclic phaserotation. A technical solution in which a time-frequency resource ismultiplexed for a plurality of reference signals in a CDM manner hasbeen clearly described in the prior art. Details are not described inthis specification.

(3) System-Supported DMRS Port

A system-supported DMRS port may be considered as a DMRS port that canbe used by a base station. During actual implementation, the basestation may schedule the terminal by using some or all DMRS portssupported by the base station. In this application, that a quantity ofsystem-supported DMRS ports is 6, 8, 12, or 16 is used as an example fordescription.

(4) Other Terms

The term “a plurality of” in this specification means at least two.

The terms “first”, “second”, and the like in this specification aremerely used to differentiate different objects, but are not intended tolimit a sequence of the terms. For example, a first symbol group and asecond symbol group are merely used to differentiate different symbolgroups, but are not intended to limit a sequence of the symbol groups.

The term “and/or” in this specification describes only an associationrelationship for describing associated objects and represents that threerelationships may exist. For example, A and/or B may represent thefollowing three cases: Only A exists, both A and B exist, and only Bexists. In addition, the character “I” in this specification generallyindicates an “or” relationship between the associated objects.

The following describes the technical solutions provided in thisapplication with reference to the accompanying drawings.

The technical solutions provided in this application may be applied tovarious communications systems, for example, current 2G, 3G, and 4Gcommunications systems, and a future evolved network such as a 5Gcommunications system. For example, the communications systems may be anLTE system, a 3rd generation partnership project (3GPP) related cellularsystem, and other communications systems. Particularly, the technicalsolutions may be applied to a 5G NR system. It should be noted that a 5Gstandard may include scenarios such as machine to machine (M2M), D2M,macro-micro communication, enhanced mobile broadband (eMBB),ultra-reliable and low latency communications (uRLLC), and massiveInternet of things communication (massive machine type communication,mMTC). These scenarios may include, but are not limited to, acommunication scenario between terminals, a communication scenariobetween base stations, a communication scenario between a base stationand a terminal, and the like. The technical solutions provided in theembodiments of this application may be further applied to a scenario ofcommunication between terminals, communication between base stations, orthe like in a 5G communications system.

The technical solutions provided in the embodiments of this applicationmay be applied to a system architecture shown in FIG. 3 . The systemarchitecture may include a base station 100 and one or more terminals200 connected to the base station 100.

In an example, the base station 100 may be implemented by using astructure shown in FIG. 4 .

The base station 100 may be a device that can communicate with theterminal 200. The base station 100 may be a relay station, an accesspoint, or the like. The base station 100 may be a base transceiverstation (BTS) in a global system for mobile communications (GSM) or acode division multiple access (CDMA) network, may be an NB (NodeB) inwideband code division multiple access (WCDMA), or may be an eNB or aneNodeB (evolutional NodeB) in LTE. Alternatively, the base station 100may be a radio controller in a cloud radio access network (CRAN)scenario. Alternatively, the base station 100 may be a network device ina future 5G network or a network device in a future evolved PLMNnetwork, or may be a wearable device, an in-vehicle device, or the like.

The terminal 200 may be user equipment (UE), an access terminal, a UEunit, a UE station, a mobile station, a mobile console, a remotestation, a remote terminal, a mobile device, a UE terminal, a terminal,a wireless communications device, a UE agent, a UE apparatus, or thelike. The access terminal may be a cellular phone, a cordless phone, asession initiation protocol (SIP) phone, a wireless local loop (WLL)station, a personal digital assistant (PDA), a handheld device having awireless communication function, a computing device, another processingdevice connected to a wireless modem, an in-vehicle device, a wearabledevice, a terminal in a future 5G network, a terminal in a futureevolved PLMN network, or the like.

A general-purpose hardware architecture of the base station 100 isdescribed. As shown in FIG. 4 , the base station may include a buildingbaseband unit (BBU) and a remote radio module (RRU). The RRU isconnected to an antenna system (that is, an antenna), and the BBU andthe RRU may be separately used based on a requirement. It should benoted that, in a specific implementation process, the base station 100may alternatively use another general-purpose hardware architecture, andis not merely limited to the general-purpose hardware architecture shownin FIG. 4 .

For example, the terminal 200 is a mobile phone, and a general-purposehardware architecture of the mobile phone is described. As shown in FIG.5 , the mobile phone may include components such as a radio frequency(RF) circuit 110, a memory 120, another input device 130, a display 140,a sensor 150, an audio circuit 160, an I/O subsystem 170, a processor180, and a power supply 190. A person skilled in the art may understandthat a structure of the mobile phone shown in FIG. 5 constitutes nolimitation on the mobile phone, and the mobile phone may includecomponents more or fewer than those shown in FIG. 5 . Some componentsmay be combined, some components may be disassembled, or thosecomponents may be disposed in different manners. A person skilled in theart may understand that the display 140 belongs to a user interface(UI), and the display 140 may include a display panel 141 and a touchpanel 142. In addition, the mobile phone may include components more orfewer than those shown in FIG. 5 . The mobile phone may further includefunction modules or devices such as a camera and a Bluetooth module,which are not shown in FIG. 5 . Details are not described herein.

Further, the processor 180 is separately connected to the RF circuit110, the memory 120, the audio circuit 160, the I/O subsystem 170, andthe power supply 190. The I/O subsystem 170 is separately connected toanother input device 130, the display 140, and the sensor 150. The RFcircuit 110 may be configured to: receive or send a signal in aninformation receiving or sending process or in a call process.Particularly, after receiving downlink information of the base station,the RF circuit 110 sends the downlink information to the processor 180for processing. The memory 120 may be configured to store a softwareprogram and module. The processor 180 processes various functionapplications and data of the mobile phone by running the softwareprogram and module that are stored in the memory 120. Another inputdevice 130 may be configured to: receive entered digit or characterinformation, and generate key signal input related to a user setting andfunction control of the mobile phone. The display 140 may be configuredto display information input by a user or information provided for auser, and various menus of the mobile phone, and may receive user input.The sensor 150 may be an optical sensor, a motion sensor, or anothersensor. The audio circuit 160 may provide an audio interface between auser and the mobile phone. The I/O subsystem 170 is configured tocontrol a peripheral device that is configured to perform input andoutput, and the peripheral device may include another device inputcontroller, a sensor controller, and a display controller. The processor180 is a control center of the mobile phone 200, and is connected to allparts of the entire mobile phone by using various interfaces and lines.The processor 180 performs various functions of the mobile phone 200 andprocesses data by running or executing the software program and/ormodule that are/is stored in the memory 120 and by invoking data storedin the memory 120, to perform overall monitoring on the mobile phone.The power supply 190 (for example, a battery) is configured to supplypower to all the foregoing components. The power supply may be logicallyconnected to the processor 180 by using a power supply managementsystem, to implement functions such as charging and dischargingmanagement and power consumption management by using the power supplymanagement system.

The technical solutions provided in this application may be used in asingle-carrier transmission scenario or a multi-carrier transmissionscenario, and may be applied to an uplink transmission scenario or adownlink transmission scenario.

The following describes a method for transmitting a DMRS provided inthis application. The method for transmitting a DMRS may include amethod for sending a DMRS by a transmit end and a method for obtaining aDMRS by a receive end.

FIG. 6 shows a method for transmitting a DMRS provided in thisapplication. The method may include the following steps.

S101. A transmit end determines a time-frequency resource used to carrya DMRS.

The DMRS is carried in at least one resource unit. For a feature of thetime-frequency resource occupied by the DMRS in each resource unit,refer to any feature of a time-frequency resource occupied by a DMRS inany one of FIG. 7 to FIG. 34 and related descriptions in FIG. 7 to FIG.34 .

S102. The transmit end sends the DMRS by using the time-frequencyresource.

S103. A receive end determines the time-frequency resource used to carrythe DMRS.

S104. The receive end obtains the DMRS by using the determinedtime-frequency resource.

The time-frequency resource used to carry the DMRS may include one ormore symbols in time domain, or may include one or more subcarriers infrequency domain. When the time-frequency resource includes a pluralityof symbols in time domain, the plurality of symbols may be a pluralityof consecutive or discrete symbols. When the time-frequency resourceincludes a plurality of subcarriers in frequency domain, the pluralityof subcarriers may be a plurality of consecutive or discretesubcarriers. This is not limited in this application. After S101 andbefore S102, the method may further include: mapping, by the transmitend, the DMRS to the determined time-frequency resource. For a relateddescription of the time-frequency resource and a beneficial effect thatcan be achieved, refer to the following descriptions.

If the technical solution is applied to an uplink transmission scenario,the transmit end may be a terminal, and the receive end may be a basestation. If the technical solution is applied to a downlink transmissionscenario, the transmit end may be a base station, and the receive endmay be a terminal.

FIG. 6 a shows another method for transmitting a DMRS provided in thisapplication. The method may include the following steps:

S201. A base station generates indication information, where theindication information is used to indicate a time-frequency resourceused to carry a DMRS.

S202. The base station sends the indication information to a terminal.

S203. The terminal receives the indication information, and determines,based on the indication information, the time-frequency resource used tocarry the DMRS.

S204. The terminal obtains the DMRS by using the determinedtime-frequency resource.

One DMRS port corresponds to one DMRS, and one DMRS may be carried onone or more REs. In one aspect, a mapping rule that is between a DMRSport and a time-frequency resource and that is used by the base stationand the terminal may be fixed, or may be semi-statically adjusted, ormay be dynamically adjusted. In another aspect, a DMRS port allocated bythe base station to the terminal may be semi-statically adjusted or maybe dynamically adjusted. Based on either of the two aspects, duringsemi-static adjustment or dynamic adjustment, a peer end may be notifiedby using an instruction. The instruction (namely, the indicationinformation) may include, but is not limited to, any one of thefollowing: radio resource control (RRC) signaling, media access control(MAC) signaling, downlink control information (DCI), and the like.

Optionally, the indication information may include DMRS portinformation, for example, a DMRS port number, and is used to indicate atime-frequency resource corresponding to the DMRS port allocated by thebase station to the terminal.

According to the method for transmitting a DMRS provided in thisapplication, a proper mapping rule between a DMRS port and atime-frequency resource is set, so that the method can be applied to acomplex and changing NR scenario.

Based on this, several mapping rules between a DMRS port and atime-frequency resource are further provided in this application. Beforethis, the following needs to be explained.

First, in this application, for ease of description, system-supportedDMRS ports may be consecutively numbered, for example, consecutivelynumbered from 1. For example, if a system supports six DMRS ports, thesix DMRS ports are denoted as DMRS ports 1 to 6. In this application,for ease of description, symbols included in a resource unit areconsecutively numbered from 0 in time domain, and subcarriers includedin the resource unit are numbered from 0 in frequency domain. Forexample, that a resource unit is an RB pair is used as an example. TheRB pair may include symbols 0 to 13 in time domain and may includesubcarriers 0 to 11 in frequency domain. Certainly, this is not limitedduring specific implementation. It should be noted that the foregoingdescription is a setting for ease of describing the technical solutionprovided in this embodiment of this application, but is not intended tolimit the scope of this application.

Second, a DMRS port may be mapped to one or more symbols of a resourceunit. Optionally, each of the one or more symbols may be a front symbol,a middle symbol, or a rear symbol of a TI. The front symbol is a symbollocated in the front of a TI, for example, may correspond to a symbolnumbered 2 (that is, a symbol 2) and/or a symbol numbered 3 (that is, asymbol 3) in a subframe in LTE. Which symbols in a subframe arespecifically defined as front symbols is not limited in thisapplication. Alternatively, each of the one or more symbols may be amiddle symbol. The middle symbol is a symbol located in the middle of asubframe, for example, may be a symbol numbered 5 (that is, a symbol 5)and/or a symbol numbered 6 (that is, a symbol 6) in the subframe. Whichsymbols in a subframe are specifically defined as middle symbols is notlimited in this application. Alternatively, each of the one or moresymbols may be a rear symbol. The rear symbol is a symbol located in therear of a subframe, for example, may be a symbol numbered 9 (that is, asymbol 9) and/or a symbol numbered 10 (that is, a symbol 10) in thesubframe. Which symbols in a subframe are specifically defined as rearsymbols is not limited in this application. It can be understood that,during actual implementation, if a DMRS port is mapped to a plurality ofsymbols, the plurality of symbols may be different types of symbols, andthe types of symbols include front symbols, middle symbols, and rearsymbols. For example, some of the plurality of symbols may be frontsymbols, and some other symbols are middle symbols.

In the following, if a DMRS port is mapped to one symbol, the symbol isreferred to as a first symbol. If a DMRS port is mapped to a pluralityof symbols, that the plurality of symbols are two symbols that arerespectively referred to as a first symbol and a second symbol is usedas an example for description. The first symbol and the second symbolmay be consecutive or may be discrete. In other words, the first symboland the second symbol may be adjacent symbols or may be non-adjacentsymbols. In all of the following specific examples, that the firstsymbol and the second symbol are consecutive is used as an example fordescription. Specifically, that the first symbol is a symbol numbered 2in a subframe and the second symbol is a symbol numbered 3 in thesubframe is used as an example for description, and this is not limitedduring actual implementation.

It can be understood that the DMRS port herein is all system-supportedDMRS ports. During actual implementation, whether all the DMRS ports areused or some of all the DMRS ports are used in one scheduling process isnot limited in this application.

It can be understood that, in this application, some or all DMRSs may bemapped to a front symbol. In this way, compared with the prior art, thisapplication allows a receive end to receive all the DMRSs more quicklyand then start data demodulation. Therefore, a requirement for rapiddata demodulation in NR can be satisfied.

Third, for a related description of a DMRS port group, refer to theforegoing descriptions. It should be noted that a specificimplementation in which specific ports are used as one DMRS port groupis not limited in this application. For example, if DMRS ports 1 to 8are divided into two groups, any four ports in the DMRS ports may beused as one DMRS port group, and the other four ports are used as oneDMRS port group. In addition, different DMRS port groups do not includea same DMRS port. For another example, if DMRS ports 1 to 12 are dividedinto three groups, any four ports in the DMRS ports may be used as oneDMRS port group, any four of other eight DMRS ports are used as one DMRSport group, and then the remaining four ports are used as one DMRS portgroup.

Fourth, the following describes a plurality of mapping rules between aDMRS port and a time-frequency resource. Specifically, the mapping rulesmay be presented by using pilot patterns. In a specific implementationprocess, the mapping rules may be implemented by using formulas ortables or in other manners. In a specific implementation process, thereceive end may learn of, by using a DMRS port or by using otherinformation used to indicate a time-frequency resource corresponding toa DMRS, the time-frequency resource corresponding to the DMRS. How thereceive end obtains the DMRS from the time-frequency resource is notlimited in this application, and this may be implemented by using amethod in the prior art. In principle, if multiplexing is performed form DMRS ports in a CDM manner, the receive end may obtain the m DMRSports from only REs whose quantity is greater than or equal to m and onwhich the m DMRS ports are carried, where m is an integer greater thanor equal to 2. A specific DMRS value (which is usually a complex number,namely, a modulation symbol) is usually selected from a value sequence.A specific selected value is loaded, by using a multiplex code used toimplement CDM, onto a plurality of REs allocated for the DMRS. For aspecific loading manner, refer to the prior art. These REs maycorrespond to different subcarriers in a same symbol, may correspond tosame subcarriers in different symbols, or may correspond to differentsubcarriers in different symbols.

Fifth, in the following, that a quantity of subcarriers of a resourceunit in frequency domain is M is used as an example for description,where M is an integer greater than or equal to 1. For example, if aresource unit is one RB pair (that is, two RBs in time domain), M=12;and if a resource unit is two RBs in frequency domain, M=24.

In addition, in the accompanying drawings of this specification, an REcorresponding to a symbol to which a DMRS port is mapped is shown, andan RE corresponding to another symbol is not shown. Information carriedon another RE is not limited in this application.

The following describes the mapping rules between a DMRS port and atime-frequency resource provided in this application.

A total quantity of system-supported DMRS ports is 6.

1. Time-frequency resources to which the six DMRS ports are mappedinclude a first symbol of a resource unit in time domain.

(1) The six DMRS ports include: a first DMRS port, a second DMRS port, athird DMRS port, a fourth DMRS port, a fifth DMRS port, and a sixth DMRSport. It should be noted that “include” specifically means “are”. Thisis similar in examples below, and therefore details are not described.Mapping rules of the six DMRS ports are as follows:

First:

A time-frequency resource to which the first DMRS port is mappedincludes a subcarrier 6n of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port is mappedincludes a subcarrier 6n+1 of the resource unit in frequency domain.

A time-frequency resource to which the third DMRS port is mappedincludes a subcarrier 6n+2 of the resource unit in frequency domain.

A time-frequency resource to which the fourth DMRS port is mappedincludes a subcarrier 6n+3 of the resource unit in frequency domain.

A time-frequency resource to which the fifth DMRS port is mappedincludes a subcarrier 6n+4 of the resource unit in frequency domain.

A time-frequency resource to which the sixth DMRS port is mappedincludes a subcarrier 6n+5 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/6┘.

In this specification, L J means rounding down. In addition, in variousmapping rules provided in this specification, if time-frequencyresources used to carry a plurality of DMRS ports (that is, carry DMRSscorresponding to the plurality of DMRS ports) do not occupy allsubcarriers of the resource unit in frequency domain, the subcarriersused to carry the DMRS ports may be offset to some extent based on arequirement. For example, after being offset, the subcarrier 6n used tocarry the first DMRS port may be changed to a subcarrier 6th+Δ, where Δis a preset offset.

(a) in FIG. 7 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS port ismapped, and n=0 or 1.

Second:

A time-frequency resource to which the first DMRS port is mappedincludes at least one of a subcarrier 12n and a subcarrier 12n+1 of theresource unit in frequency domain.

A time-frequency resource to which the second DMRS port is mappedincludes at least one of a subcarrier 12n+2 and a subcarrier 12n+3 ofthe resource unit in frequency domain.

A time-frequency resource to which the third DMRS port is mappedincludes at least one of a subcarrier 12n+4 and a subcarrier 12n+5 ofthe resource unit in frequency domain.

A time-frequency resource to which the fourth DMRS port is mappedincludes at least one of a subcarrier 12n+6 and a subcarrier 12n+7 ofthe resource unit in frequency domain.

A time-frequency resource to which the fifth DMRS port is mappedincludes at least one of a subcarrier 12n+8 and a subcarrier 12n+9 ofthe resource unit in frequency domain.

A time-frequency resource to which the sixth DMRS port is mappedincludes at least one of a subcarrier 12n+10 and a subcarrier 12n+11 ofthe resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan or equal to └M/12┘.

(b) in FIG. 7 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

(2) The six DMRS ports are divided into three DMRS port groups, and eachDMRS port group includes two DMRS ports. The three DMRS port groupsinclude a first DMRS port group, a second DMRS port group, and a thirdDMRS port group. A same time-frequency resource is multiplexed in a CDMmanner for DMRSs corresponding to DMRS ports in each DMRS port group.Mapping rules of the three DMRS port groups are as follows:

First:

A time-frequency resource to which the first DMRS port group is mappedincludes a subcarrier 3n of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes a subcarrier 3n+1 of the resource unit in frequency domain.

A time-frequency resource to which the third DMRS port group is mappedincludes a subcarrier 3n+2 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/3 ┘.

(a) in FIG. 8 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, or 3. For example, any three ports inthe DMRS ports may be used as one DMRS port group, and the other threeports may be used as one DMRS port group. For example, DMRS ports 1 to 3are used as a first DMRS port group, and DMRS ports 4 to 6 are used as asecond DMRS port group. Certainly, this is not limited during specificimplementation. In this solution, the ports are evenly distributed infrequency domain and have a high density. This ensures high channelestimation accuracy in various scenarios. In addition, the ports areevenly distributed but are mutually discrete in frequency domain.Therefore, this solution has a feature of a low peak-to-average powerratio (PAPR), and is applicable to both a multi-carrier transmissionscenario and a single-carrier transmission scenario, therebyfacilitating joint design of uplink and downlink transmission ormulti-waveform transmission; and this solution is applicable to amulti-user MIMO (MU-MIMO) scenario (MU-MIMO scenario), thereby reducingDMRS indication overheads and design complexity of a system. In thissolution, only one symbol is occupied. Therefore, system overheads arelow, and this solution can be used in a high-frequency scenario. Thissolution may further support more ports in a manner of adding symbols,and therefore flexibility is better. In addition, the ports are evenlymapped in frequency domain, thereby facilitating flexible scheduling.Further, power boosting or data transmission may be performed at alocation of an unoccupied port group.

Second:

A time-frequency resource to which the first DMRS port group is mappedincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+6, and a subcarrier 12n+7 of the resource unit infrequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes at least one of a subcarrier 12n+2, a subcarrier 12n+3, asubcarrier 12n+8, and a subcarrier 12n+9 of the resource unit infrequency domain.

A time-frequency resource to which the third DMRS port group is mappedincludes at least one of a subcarrier 12n+4, a subcarrier 12n+5, asubcarrier 12n+10, and a subcarrier 12n+11 of the resource unit infrequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(b) in FIG. 8 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

(3) The six DMRS ports are divided into two DMRS port groups, and eachDMRS port group includes three DMRS ports. The two DMRS port groupsinclude a first DMRS port group and a second DMRS port group. A sametime-frequency resource is multiplexed in a CDM manner for DMRSscorresponding to DMRS ports in each DMRS port group. Mapping rules ofthe two DMRS port groups are as follows:

First:

A time-frequency resource to which the first DMRS port group is mappedincludes a subcarrier 2n of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes a subcarrier 2n+1 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/2┘.

(a) in FIG. 9 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, 3, 4, or 5. In this solution, the portsare evenly distributed in frequency domain and have a high density. Thisensures high channel estimation accuracy in various scenarios. Inaddition, the ports are evenly distributed but are mutually discrete infrequency domain. Therefore, this solution has a feature of a low PAPR,and is applicable to both a multi-carrier transmission scenario and asingle-carrier transmission scenario, thereby facilitating joint designof uplink and downlink transmission or multi-waveform transmission; andthis solution is applicable to an MU-MIMO scenario, thereby reducingDMRS indication overheads and design complexity of a system. In thissolution, only one symbol is occupied. Therefore, system overheads arelow, and this solution can be used in a high-frequency scenario. Thissolution may further support more ports in a manner of adding symbols,and therefore flexibility is better. In addition, the ports are evenlymapped in frequency domain, thereby facilitating flexible scheduling.Further, power boosting or data transmission may be performed at alocation of an unoccupied port group.

Second:

A time-frequency resource to which the first DMRS port group is mappedincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+2, a subcarrier 12n+6, a subcarrier 12n+7, and asubcarrier 12n+8 of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes at least one of a subcarrier 12n+3, a subcarrier 12n+4, asubcarrier 12n+5, a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(b) in FIG. 9 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

(4) A same time-frequency resource is multiplexed in a CDM manner forDMRSs corresponding to the six DMRS ports. In this case, the six DMRSports may be considered as one DMRS port group. Mapping rules of theDMRS port group are as follows:

First:

A time-frequency resource to which the DMRS port group is mappedincludes a subcarrier 2n of the resource unit in frequency domain; or

a time-frequency resource to which the DMRS port group is mappedincludes a subcarrier 2n+1 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/2┘.

(a) in FIG. 10 is a schematic diagram of a mapping rule of the six DMRSports. In the figure, that a time-frequency resource to which the DMRSport group is mapped includes the subcarrier 2n of the resource unit infrequency domain is used as an example for description. Each smallshaded block indicates an RE to which a DMRS port group is mapped, andn=0, 1, 2, 3, 4, or 5. A small blank block indicates an RE to which aDMRS port is not mapped.

Second:

A time-frequency resource to which the DMRS port group is mappedincludes a subcarrier n of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan M.

(b) in FIG. 10 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11.

2. Time-frequency resources to which the six DMRS ports are mappedinclude a first symbol and a second symbol of a resource unit in timedomain.

(1) The six DMRS ports include: a first DMRS port, a second DMRS port, athird DMRS port, a fourth DMRS port, a fifth DMRS port, and a sixth DMRSport. Mapping rules of the six DMRS ports are as follows:

First: The time-frequency resources to which the six DMRS ports aremapped include subcarriers of the resource unit in frequency domain,where the subcarriers are the same as those in the first solutioncorresponding to (a) in FIG. 7 . In this case, an example is shown in(a) in FIG. 11 .

Second: The time-frequency resources to which the six DMRS ports aremapped include subcarriers of the resource unit in frequency domain,where the subcarriers are the same as those in the second solutioncorresponding to (b) in FIG. 7 . In this case, an example is shown in(b) in FIG. 11 .

Third: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port is mapped isthe first symbol in time domain, the time-frequency resource includes asubcarrier 6n of the resource unit in frequency domain; and when atime-frequency resource to which the first DMRS port is mapped is thesecond symbol in time domain, the time-frequency resource includes asubcarrier 6n+3 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port is mappedis the first symbol in time domain, the time-frequency resource includesa subcarrier 6n+1 of the resource unit in frequency domain; and when atime-frequency resource to which the second DMRS port is mapped is thesecond symbol in time domain, the time-frequency resource includes asubcarrier 6n+4 of the resource unit in frequency domain.

When a time-frequency resource to which the third DMRS port is mapped isthe first symbol in time domain, the time-frequency resource includes asubcarrier 6n+2 of the resource unit in frequency domain; and when atime-frequency resource to which the third DMRS port is mapped is thesecond symbol in time domain, the time-frequency resource includes asubcarrier 6n+5 of the resource unit in frequency domain.

When a time-frequency resource to which the fourth DMRS port is mappedis the first symbol in time domain, the time-frequency resource includesa subcarrier 6n+3 of the resource unit in frequency domain; and when atime-frequency resource to which the fourth DMRS port is mapped is thesecond symbol in time domain, the time-frequency resource includes asubcarrier 6n of the resource unit in frequency domain.

When a time-frequency resource to which the fifth DMRS port is mapped isthe first symbol in time domain, the time-frequency resource includes asubcarrier 6n+4 of the resource unit in frequency domain; and when atime-frequency resource to which the fifth DMRS port is mapped is thesecond symbol in time domain, the time-frequency resource includes asubcarrier 6n+1 of the resource unit in frequency domain.

When a time-frequency resource to which the sixth DMRS port is mapped isthe first symbol in time domain, the time-frequency resource includes asubcarrier 6n+5 of the resource unit in frequency domain; and when atime-frequency resource to which the sixth DMRS port is mapped is thesecond symbol in time domain, the time-frequency resource includes asubcarrier 6n+2 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/6┘.

(c) in FIG. 11 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS port ismapped, and n=0 or 1.

Fourth: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port is mapped isthe first symbol in time domain, the time-frequency resource includes atleast one of a subcarrier 12n and a subcarrier 12n+1 of the resourceunit in frequency domain; and when a time-frequency resource to whichthe first DMRS port is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+6 anda subcarrier 12n+7 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port is mappedis the first symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+2 and a subcarrier 12n+3 of theresource unit in frequency domain; and when a time-frequency resource towhich the second DMRS port is mapped is the second symbol in timedomain, the time-frequency resource includes at least one of asubcarrier 12n+8 and a subcarrier 12n+9 of the resource unit infrequency domain.

When a time-frequency resource to which the third DMRS port is mapped isthe first symbol in time domain, the time-frequency resource includes atleast one of a subcarrier 12n+4 and a subcarrier 12n+5 of the resourceunit in frequency domain; and when a time-frequency resource to whichthe third DMRS port is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+10 anda subcarrier 12n+11 of the resource unit in frequency domain.

When a time-frequency resource to which the fourth DMRS port is mappedis the first symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+6 and a subcarrier 12n+7 of theresource unit in frequency domain; and when a time-frequency resource towhich the fourth DMRS port is mapped is the second symbol in timedomain, the time-frequency resource includes at least one of asubcarrier 12n and a subcarrier 12n+1 of the resource unit in frequencydomain.

When a time-frequency resource to which the fifth DMRS port is mapped isthe first symbol in time domain, the time-frequency resource includes atleast one of a subcarrier 12n+8 and a subcarrier 12n+9 of the resourceunit in frequency domain; and when a time-frequency resource to whichthe fifth DMRS port is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+2 anda subcarrier 12n+3 of the resource unit in frequency domain.

When a time-frequency resource to which the sixth DMRS port is mapped isthe first symbol in time domain, the time-frequency resource includes atleast one of a subcarrier 12n+10 and a subcarrier 12n+11 of the resourceunit in frequency domain; and when a time-frequency resource to whichthe sixth DMRS port is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+4 anda subcarrier 12n+5 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan or equal to └M/12┘.

(d) in FIG. 11 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

(2) The six DMRS ports are divided into three DMRS port groups, and eachDMRS port group includes two DMRS ports. The three DMRS port groupsinclude a first DMRS port group, a second DMRS port group, and a thirdDMRS port group. A same time-frequency resource is multiplexed in a CDMmanner for DMRSs corresponding to DMRS ports in each DMRS port group.Mapping rules of the three DMRS port groups are as follows:

First: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the first solutioncorresponding to (a) in FIG. 8 . In this case, an example is shown in(a) in FIG. 12 . In this solution, the ports are evenly distributed infrequency domain and distributed on the two symbols, and have a highdensity. This ensures high channel estimation accuracy in variousscenarios. In addition, the ports are evenly distributed but aremutually discrete in frequency domain. Therefore, this solution has afeature of a low PAPR, and is applicable to both a multi-carriertransmission scenario and a single-carrier transmission scenario,thereby facilitating joint design of uplink and downlink transmission ormulti-waveform transmission; and this solution is applicable to anMU-MIMO scenario, thereby reducing DMRS indication overheads and designcomplexity of a system. In addition, in this solution, a method forperforming multiplexing for more ports in each port group supportstransmission through more ports without changing an original portmapping. Therefore, this solution is more generally used. In addition,the ports are evenly mapped in frequency domain, thereby facilitatingflexible scheduling. Further, power boosting or data transmission may beperformed at a location of an unoccupied port group. A CDM length issmall, thereby ensuring better orthogonality between the ports.

Second: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the second solutioncorresponding to (b) in FIG. 8 . In this case, an example is shown in(b) in FIG. 12 .

Third: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n of the resource unit in frequency domain; andwhen a time-frequency resource to which the first DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+2 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+1 of the resource unit in frequency domain; andwhen a time-frequency resource to which the second DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n of the resource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+2 of the resource unit in frequency domain; andwhen a time-frequency resource to which the third DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+1 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/3┘.

(c) in FIG. 12 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, or 3.

Fourth: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n of the resource unit in frequency domain; andwhen a time-frequency resource to which the first DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+1 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+1 of the resource unit in frequency domain; andwhen a time-frequency resource to which the second DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+2 of the resource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+2 of the resource unit in frequency domain; andwhen a time-frequency resource to which the third DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/3┘.

(d) in FIG. 12 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, or 3.

Fifth: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+6, and a subcarrier 12n+7 of the resource unit infrequency domain; and when a time-frequency resource to which the firstDMRS port group is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+4, asubcarrier 12n+5, a subcarrier 12n+10, and a subcarrier 12n+11 of theresource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+2, a subcarrier 12n+3, asubcarrier 12n+8, and a subcarrier 12n+9 of the resource unit infrequency domain; and when a time-frequency resource to which the secondDMRS port group is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n, asubcarrier 12n+1, a subcarrier 12n+6, and a subcarrier 12n+7 of theresource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+4, a subcarrier 12n+5, asubcarrier 12n+10, and a subcarrier 12n+11 of the resource unit infrequency domain; and when a time-frequency resource to which the thirdDMRS port group is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+2, asubcarrier 12n+3, a subcarrier 12n+8, and a subcarrier 12n+9 of theresource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(e) in FIG. 12 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Sixth: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+6, and a subcarrier 12n+7 of the resource unit infrequency domain; and when a time-frequency resource to which the firstDMRS port group is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+2, asubcarrier 12n+3, a subcarrier 12n+8, and a subcarrier 12n+9 of theresource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+2, a subcarrier 12n+3, asubcarrier 12n+8, and a subcarrier 12n+9 of the resource unit infrequency domain; and when a time-frequency resource to which the secondDMRS port group is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+4, asubcarrier 12n+5, a subcarrier 12n+10, and a subcarrier 12n+11 of theresource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+4, a subcarrier 12n+5, asubcarrier 12n+10, and a subcarrier 12n+11 of the resource unit infrequency domain; and when a time-frequency resource to which the thirdDMRS port group is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n, asubcarrier 12n+1, a subcarrier 12n+6, and a subcarrier 12n+7 of theresource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(f) in FIG. 12 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

(3) The six DMRS ports are divided into two DMRS port groups, and eachDMRS port group includes three DMRS ports. The two DMRS port groupsinclude a first DMRS port group and a second DMRS port group. A sametime-frequency resource is multiplexed in a CDM manner for DMRSscorresponding to DMRS ports in each DMRS port group. Mapping rules ofthe two DMRS port groups are as follows:

First: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the first solutioncorresponding to (a) in FIG. 9 . In this case, an example is shown in(a) in FIG. 13 . In this solution, the ports are evenly distributed infrequency domain and distributed on both the symbols, and have a highdensity. This ensures high channel estimation accuracy in variousscenarios. In addition, the ports are evenly distributed but aremutually discrete in frequency domain. Therefore, this solution has afeature of a low PAPR, and is applicable to both a multi-carriertransmission scenario and a single-carrier transmission scenario,thereby facilitating joint design of uplink and downlink transmission ormulti-waveform transmission; and this solution is applicable to anMU-MIMO scenario, thereby reducing DMRS indication overheads and designcomplexity of a system. In addition, in this solution, a method forperforming multiplexing for more ports in each port group supportstransmission through more ports without changing an original portmapping. Therefore, this solution is more generally used. In addition,the ports are evenly mapped in frequency domain, thereby facilitatingflexible scheduling. Further, power boosting or data transmission may beperformed at a location of an unoccupied port group. In addition, a CDMlength in a port group is small, thereby ensuring better orthogonalitybetween the ports.

Second: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the second solutioncorresponding to (b) in FIG. 9 . In this case, an example is shown in(b) in FIG. 13 .

Third: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 2n of the resource unit in frequency domain; andwhen a time-frequency resource to which the first DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 2n+1 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 2n+1 of the resource unit in frequency domain; andwhen a time-frequency resource to which the second DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 2n of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/2┘.

(c) in FIG. 13 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, 3, 4, or 5.

Fourth: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+2, a subcarrier 12n+6, a subcarrier 12n+7, and asubcarrier 12n+8 of the resource unit in frequency domain; and when atime-frequency resource to which the first DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+3, a subcarrier 12n+4, a subcarrier12n+5, a subcarrier 12n+9, a subcarrier 12n+10, and a subcarrier 12n+11of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+3, a subcarrier 12n+4, asubcarrier 12n+5, a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain; and when atime-frequency resource to which the second DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n, a subcarrier 12n+1, a subcarrier12n+2, a subcarrier 12n+6, a subcarrier 12n+7, and a subcarrier 12n+8 ofthe resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(d) in FIG. 13 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Fifth: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol and the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n, asubcarrier 12n+1, a subcarrier 12n+4, a subcarrier 12n+5, a subcarrier12n+8, and a subcarrier 12n+9 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol and the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+2, asubcarrier 12n+3, a subcarrier 12n+6, a subcarrier 12n+7, a subcarrier12n+10, and a subcarrier 12n+11 of the resource unit in frequencydomain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(e) in FIG. 13 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Sixth: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+4, a subcarrier 12n+5, a subcarrier 12n+8, and asubcarrier 12n+9 of the resource unit in frequency domain; and when atime-frequency resource to which the first DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+2, a subcarrier 12n+3, a subcarrier12n+6, a subcarrier 12n+7, a subcarrier 12n+10, and a subcarrier 12n+11of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+2, a subcarrier 12n+3, asubcarrier 12n+6, a subcarrier 12n+7, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain; and when atime-frequency resource to which the second DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n, a subcarrier 12n+1, a subcarrier12n+4, a subcarrier 12n+5, a subcarrier 12n+8, and a subcarrier 12n+9 ofthe resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(f) in FIG. 13 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

(4) A same time-frequency resource is multiplexed in a CDM manner forDMRSs corresponding to the six DMRS ports. In this case, the six DMRSports may be considered as one DMRS port group. Mapping rules of theDMRS port group are as follows:

First: A time-frequency resource to which the DMRS port group is mappedincludes the first symbol and the second symbol; and for thetime-frequency resource to which the DMRS port group is mapped infrequency domain, reference may be made to the first solutioncorresponding to (a) in FIG. 10 . In this case, an example is shown in(a) in FIG. 14 .

Second: A time-frequency resource to which the DMRS port group is mappedincludes the first symbol and the second symbol; and for thetime-frequency resource to which the DMRS port group is mapped infrequency domain, reference may be made to the second solutioncorresponding to (b) in FIG. 10 . In this case, an example is shown in(b) in FIG. 14 .

Third:

When a time-frequency resource to which the DMRS port group is mapped isthe first symbol in time domain, the time-frequency resource includes asubcarrier 2n of the resource unit in frequency domain; and when atime-frequency resource to which the DMRS port group is mapped is thesecond symbol in time domain, the time-frequency resource includes asubcarrier 2n+1 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/2┘.

(c) in FIG. 14 is a schematic diagram of a mapping rule of the six DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, 3, 4, or 5. A small blank blockindicates an RE to which a DMRS port is not mapped.

A total quantity of system-supported DMRS ports is 8.

1. Time-frequency resources to which the eight DMRS ports are mappedinclude a first symbol of a resource unit in time domain.

The eight DMRS ports are divided into four DMRS port groups, and eachDMRS port group includes two DMRS ports. The four DMRS port groupsinclude a first DMRS port group, a second DMRS port group, a third DMRSport group, and a fourth DMRS port group. A same time-frequency resourceis multiplexed in a CDM manner for DMRSs corresponding to DMRS ports ineach DMRS port group. Mapping rules of the four DMRS port groups are asfollows:

A time-frequency resource to which the first DMRS port group is mappedincludes at least one of a subcarrier 12n, a subcarrier 12n+1, and asubcarrier 12n+2 of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes at least one of a subcarrier 12n+3, a subcarrier 12n+4, and asubcarrier 12n+5 of the resource unit in frequency domain.

A time-frequency resource to which the third DMRS port group is mappedincludes at least one of a subcarrier 12n+6, a subcarrier 12n+7, and asubcarrier 12n+8 of the resource unit in frequency domain.

A time-frequency resource to which the fourth DMRS port group is mappedincludes at least one of a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

FIG. 15 is a schematic diagram of a mapping rule of the eight DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

2. Time-frequency resources to which the eight DMRS ports are mappedinclude a first symbol and a second symbol of a resource unit in timedomain.

(1) The eight DMRS ports are divided into four DMRS port groups, andeach DMRS port group includes two DMRS ports. The four DMRS port groupsinclude a first DMRS port group, a second DMRS port group, a third DMRSport group, and a fourth DMRS port group. A same time-frequency resourceis multiplexed in a CDM manner for DMRSs corresponding to DMRS ports ineach DMRS port group. Mapping rules of the four DMRS port groups are asfollows:

First: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the solution corresponding toFIG. 15 . In this case, an example is shown in (a) in FIG. 16 .

Second: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, and asubcarrier 12n+2 of the resource unit in frequency domain; and when atime-frequency resource to which the first DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+6, a subcarrier 12n+7, and a subcarrier12n+8 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+3, a subcarrier 12n+4, and asubcarrier 12n+5 of the resource unit in frequency domain; and when atime-frequency resource to which the second DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+6, a subcarrier 12n+7, and asubcarrier 12n+8 of the resource unit in frequency domain; and when atime-frequency resource to which the third DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n, a subcarrier 12n+1, and a subcarrier12n+2 of the resource unit in frequency domain.

When a time-frequency resource to which the fourth DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain; and when atime-frequency resource to which the fourth DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+3, a subcarrier 12n+4, and a subcarrier12n+5 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(b) in FIG. 16 is a schematic diagram of a mapping rule of the eightDMRS ports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Third: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+4, and asubcarrier 12n+8 of the resource unit in frequency domain; and when atime-frequency resource to which the first DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+2, a subcarrier 12n+6, and a subcarrier12n+10 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+1, a subcarrier 12n+5, and asubcarrier 12n+9 of the resource unit in frequency domain; and when atime-frequency resource to which the second DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+3, a subcarrier 12n+7, and a subcarrier12n+11 of the resource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+2, a subcarrier 12n+6, and asubcarrier 12n+10 of the resource unit in frequency domain; and when atime-frequency resource to which the third DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n, a subcarrier 12n+4, and a subcarrier12n+8 of the resource unit in frequency domain.

When a time-frequency resource to which the fourth DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+3, a subcarrier 12n+7, and asubcarrier 12n+11 of the resource unit in frequency domain; and when atime-frequency resource to which the fourth DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+1, a subcarrier 12n+5, and a subcarrier12n+9 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(c) in FIG. 16 is a schematic diagram of a mapping rule of the eightDMRS ports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Fourth: Time-frequency resources to which the first and second DMRS portgroups are mapped include the first symbol in time domain, andtime-frequency resources to which the third and fourth DMRS port groupsare mapped include the second symbol in time domain.

When the time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 2n of the resource unit in frequency domain.

When the time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 2n+1 of the resource unit in frequency domain.

When the time-frequency resource to which the third DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 2n of the resource unit in frequency domain.

When the time-frequency resource to which the fourth DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 2n+1 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/2┘.

(d) in FIG. 16 is a schematic diagram of a mapping rule of the eightDMRS ports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, 3, 4, or 5. In this solution, the portsare evenly distributed in frequency domain and have a high density. Thisensures high channel estimation accuracy in various scenarios. Inaddition, the ports are evenly distributed but are mutually discrete infrequency domain. Therefore, this solution has a feature of a low PAPR,and is applicable to both a multi-carrier transmission scenario and asingle-carrier transmission scenario, thereby facilitating joint designof uplink and downlink transmission or multi-waveform transmission; andthis solution is applicable to an MU-MIMO scenario, thereby reducingDMRS indication overheads and design complexity of a system. In thissolution, each port is mapped to only one symbol. Therefore, phase noiseimpact is avoided, and this solution may be used in a high-frequencyscenario. In this solution, different quantities of symbols may also beused for different ports, and a port mapping location is fixed.Therefore, flexibility is better, performance is ensured, and overheadsare reduced. In addition, the ports are evenly mapped in frequencydomain, thereby facilitating flexible scheduling.

(2) The eight DMRS ports are divided into two DMRS port groups, and eachDMRS port group includes four DMRS ports. The two DMRS port groupsinclude a first DMRS port group and a second DMRS port group. A sametime-frequency resource is multiplexed in a CDM manner for DMRSscorresponding to DMRS ports in each DMRS port group. Mapping rules ofthe two DMRS port groups are as follows:

First: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol and the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n, asubcarrier 12n+1, a subcarrier 12n+4, a subcarrier 12n+5, a subcarrier12n+8, and a subcarrier 12n+9 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol and the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+2, asubcarrier 12n+3, a subcarrier 12n+6, a subcarrier 12n+7, a subcarrier12n+10, and a subcarrier 12n+11 of the resource unit in frequencydomain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(a) in FIG. 17 is a schematic diagram of a mapping rule of the eightDMRS ports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0. In this solution, the ports are evenlydistributed in two symbols in time domain and in frequency domain andhave a high density. This ensures high channel estimation accuracy invarious scenarios. In addition, this solution is applicable to aplurality of types of carrier systems, and uplink and downlink systems,thereby reducing DMRS indication overheads and design complexity. Inthis solution, each port is mapped to only consecutive REs, so thatorthogonality between ports in a port group is less affected by achannel. This ensures channel estimation accuracy. In addition, theports are evenly mapped in frequency domain, thereby facilitatingflexible scheduling. Further, power boosting or data transmission may beperformed at a location of an unoccupied port group.

Second: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+4, a subcarrier 12n+5, a subcarrier 12n+8, and asubcarrier 12n+9 of the resource unit in frequency domain; and when atime-frequency resource to which the first DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+2, a subcarrier 12n+3, a subcarrier12n+6, a subcarrier 12n+7, a subcarrier 12n+10, and a subcarrier 12n+11of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+2, a subcarrier 12n+3, asubcarrier 12n+6, a subcarrier 12n+7, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain; and when atime-frequency resource to which the second DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n, a subcarrier 12n+1, a subcarrier12n+4, a subcarrier 12n+5, a subcarrier 12n+8, and a subcarrier 12n+9 ofthe resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(b) in FIG. 17 is a schematic diagram of a mapping rule of the eightDMRS ports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Third: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 2n of the resource unit in frequency domain; andwhen a time-frequency resource to which the first DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 2n+1 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 2n+1 of the resource unit in frequency domain; andwhen a time-frequency resource to which the second DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 2n of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/2┘.

(c) in FIG. 17 is a schematic diagram of a mapping rule of the eightDMRS ports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, 3, 4, or 5.

Fourth: A time-frequency resource to which the first DMRS port group ismapped includes the first symbol in time domain, and a time-frequencyresource to which the second DMRS port group is mapped includes thesecond symbol in time domain.

When the time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier n of the resource unit in frequency domain.

When the time-frequency resource to which the second DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier n of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan M.

(d) in FIG. 17 is a schematic diagram of a mapping rule of the eightDMRS ports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11.

(3) A same time-frequency resource is multiplexed in a CDM manner forDMRSs corresponding to the eight DMRS ports. In this case, the eightDMRS ports may be considered as one DMRS port group. Mapping rules ofthe DMRS port group are as follows:

When a time-frequency resource to which the DMRS port group is mappedincludes the first symbol and the second symbol in time domain, thetime-frequency resource includes a subcarrier n of the resource unit infrequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan M.

FIG. 18 is a schematic diagram of a mapping rule of the eight DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11.

A total quantity of system-supported DMRS ports is 12.

1. Time-frequency resources to which the 12 DMRS ports are mappedinclude a first symbol of a resource unit in time domain.

(1) The 12 DMRS ports are divided into six DMRS port groups, and eachDMRS port group includes two DMRS ports. The six DMRS port groupsinclude a first DMRS port group, a second DMRS port group, a third DMRSport group, a fourth DMRS port group, a fifth DMRS port group, and asixth DMRS port group. A same time-frequency resource is multiplexed ina CDM manner for DMRSs corresponding to DMRS ports in each DMRS portgroup. Mapping rules of the six DMRS port groups are as follows:

First:

A time-frequency resource to which the first DMRS port group is mappedincludes at least one of a subcarrier 12n and a subcarrier 12n+1 of theresource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes at least one of a subcarrier 12n+2 and a subcarrier 12n+3 ofthe resource unit in frequency domain.

A time-frequency resource to which the third DMRS port group is mappedincludes at least one of a subcarrier 12n+4 and a subcarrier 12n+5 ofthe resource unit in frequency domain.

A time-frequency resource to which the fourth DMRS port group is mappedincludes at least one of a subcarrier 12n+6 and a subcarrier 12n+7 ofthe resource unit in frequency domain.

A time-frequency resource to which the fifth DMRS port group is mappedincludes at least one of a subcarrier 12n+8 and a subcarrier 12n+9 ofthe resource unit in frequency domain.

A time-frequency resource to which the sixth DMRS port group is mappedincludes at least one of a subcarrier 12n+10 and a subcarrier 12n+11 ofthe resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(a) in FIG. 19 is a schematic diagram of a mapping rule of the twelveDMRS ports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Second:

A time-frequency resource to which the first DMRS port group is mappedincludes a subcarrier 6n of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes a subcarrier 6n+1 of the resource unit in frequency domain.

A time-frequency resource to which the third DMRS port group is mappedincludes a subcarrier 6n+2 of the resource unit in frequency domain.

A time-frequency resource to which the fourth DMRS port group is mappedincludes a subcarrier 6n+3 of the resource unit in frequency domain.

A time-frequency resource to which the fifth DMRS port group is mappedincludes a subcarrier 6n+4 of the resource unit in frequency domain.

A time-frequency resource to which the sixth DMRS port group is mappedincludes a subcarrier 6n+5 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/6┘.

(b) in FIG. 19 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0 or 1. The ports are evenly distributed but aremutually discrete in frequency domain. Therefore, this solution has afeature of a low PAPR, and is applicable to both a multi-carriertransmission scenario and a single-carrier transmission scenario,thereby facilitating joint design of uplink and downlink transmission ormulti-waveform transmission; and this solution is applicable to anMU-MIMO scenario, thereby reducing DMRS indication overheads and designcomplexity of a system. In this solution, only one symbol is occupied.Therefore, system overheads are low, and this solution can be used in ahigh-frequency scenario. This solution may further support more ports ina manner of adding symbols, and therefore flexibility is better. Inaddition, the ports are evenly mapped in frequency domain, therebyfacilitating flexible scheduling. Further, power boosting or datatransmission may be performed at a location of an unoccupied port group.In addition, in this solution, a port mapping location is fixed, a samepilot pattern is used for different ports, and therefore systemindication overheads are reduced.

(2) The 12 DMRS ports are divided into four DMRS port groups, and eachDMRS port group includes three DMRS ports. The four DMRS port groupsinclude a first DMRS port group, a second DMRS port group, a third DMRSport group, and a fourth DMRS port group. A same time-frequency resourceis multiplexed in a CDM manner for DMRSs corresponding to DMRS ports ineach DMRS port group. Mapping rules of the four DMRS port groups are asfollows:

A time-frequency resource to which the first DMRS port group is mappedincludes at least one of a subcarrier 12n, a subcarrier 12n+1, and asubcarrier 12n+2 of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes at least one of a subcarrier 12n+3, a subcarrier 12n+4, and asubcarrier 12n+5 of the resource unit in frequency domain.

A time-frequency resource to which the third DMRS port group is mappedincludes at least one of a subcarrier 12n+6, a subcarrier 12n+7, and asubcarrier 12n+8 of the resource unit in frequency domain.

A time-frequency resource to which the fourth DMRS port group is mappedincludes at least one of a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(a) in FIG. 20 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

(3) The 12 DMRS ports are divided into three DMRS port groups, and eachDMRS port group includes four DMRS ports. The three DMRS port groupsinclude a first DMRS port group, a second DMRS port group, and a thirdDMRS port group. A same time-frequency resource is multiplexed in a CDMmanner for DMRSs corresponding to DMRS ports in each DMRS port group.Mapping rules of the three DMRS port groups are as follows:

A time-frequency resource to which the first DMRS port group is mappedincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+2, and a subcarrier 12n+3 of the resource unit infrequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes at least one of a subcarrier 12n+4, a subcarrier 12n+5, asubcarrier 12n+6, and a subcarrier 12n+7 of the resource unit infrequency domain.

A time-frequency resource to which the third DMRS port group is mappedincludes at least one of a subcarrier 12n+8, a subcarrier 12n+9, asubcarrier 12n+10, and a subcarrier 12n+11 of the resource unit infrequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(b) in FIG. 20 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

(4) The 12 DMRS ports are divided into two DMRS port groups, and eachDMRS port group includes six DMRS ports. The two DMRS port groupsinclude a first DMRS port group and a second DMRS port group. A sametime-frequency resource is multiplexed in a CDM manner for DMRSscorresponding to DMRS ports in each DMRS port group. Mapping rules ofthe two DMRS port groups are as follows:

First:

A time-frequency resource to which the first DMRS port group is mappedincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+2, a subcarrier 12n+3, a subcarrier 12n+4, and asubcarrier 12n+5 of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes at least one of a subcarrier 12n+6, a subcarrier 12n+7, asubcarrier 12n+8, a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(a) in FIG. 21 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Second:

A time-frequency resource to which the first DMRS port group is mappedincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+2, a subcarrier 12n+6, a subcarrier 12n+7, and asubcarrier 12n+8 of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes at least one of a subcarrier 12n+3, a subcarrier 12n+4, asubcarrier 12n+5, a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(b) in FIG. 21 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Third:

A time-frequency resource to which the first DMRS port group is mappedincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+4, a subcarrier 12n+5, a subcarrier 12n+8, and asubcarrier 12n+9 of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes at least one of a subcarrier 12n+2, a subcarrier 12n+3, asubcarrier 12n+6, a subcarrier 12n+7, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(c) in FIG. 21 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Fourth:

A time-frequency resource to which the first DMRS port group is mappedincludes a subcarrier 2n of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes a subcarrier 2n+1 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/2┘.

(d) in FIG. 21 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, 3, 4, or 5. In this solution, the portsare evenly distributed in frequency domain and have a high density. Thisensures high channel estimation accuracy in various scenarios. Inaddition, the ports are evenly distributed but are mutually discrete infrequency domain. Therefore, this solution has a feature of a low PAPR,and is applicable to both a multi-carrier transmission scenario and asingle-carrier transmission scenario, thereby facilitating joint designof uplink and downlink transmission or multi-waveform transmission; andthis solution is applicable to an MU-MIMO scenario, thereby reducingDMRS indication overheads and design complexity of a system. In thissolution, only one symbol is occupied. Therefore, system overheads arelow, and this solution can be used in a high-frequency scenario. Inaddition, the ports are evenly mapped in frequency domain, therebyfacilitating flexible scheduling. Further, power boosting or datatransmission may be performed at a location of an unoccupied port group.A port mapping location is fixed, a same pilot pattern is used fordifferent ports, and therefore system indication overheads are reduced.

(4) A same time-frequency resource is multiplexed in a CDM manner forDMRSs corresponding to the 12 DMRS ports. In this case, the 12 DMRSports may be considered as one DMRS port group. Mapping rules of theDMRS port group are as follows:

A time-frequency resource to which the DMRS port group is mappedincludes a subcarrier n of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan M.

FIG. 22 is a schematic diagram of a mapping rule of the 12 DMRS ports.Each small shaded block indicates an RE to which a DMRS port group ismapped, and n=0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11.

2. Time-frequency resources to which the 12 DMRS ports are mappedinclude a first symbol and a second symbol of a resource unit in timedomain.

(1) The 12 DMRS ports are divided into six DMRS port groups, and eachDMRS port group includes two DMRS ports. The six DMRS port groupsinclude a first DMRS port group, a second DMRS port group, a third DMRSport group, a fourth DMRS port group, a fifth DMRS port group, and asixth DMRS port group. A same time-frequency resource is multiplexed ina CDM manner for DMRSs corresponding to DMRS ports in each DMRS portgroup. Mapping rules of the six DMRS port groups are as follows:

First: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the solution corresponding to(a) in FIG. 19 . In this case, an example is shown in (a) in FIG. 23 .

Second: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n and a subcarrier 12n+1 of theresource unit in frequency domain; and when a time-frequency resource towhich the first DMRS port group is mapped is the second symbol in timedomain, the time-frequency resource includes at least one of asubcarrier 12n+6 and a subcarrier 12n+7 of the resource unit infrequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+2 and a subcarrier 12n+3 ofthe resource unit in frequency domain; and when a time-frequencyresource to which the second DMRS port group is mapped is the secondsymbol in time domain, the time-frequency resource includes at least oneof a subcarrier 12n+8 and a subcarrier 12n+9 of the resource unit infrequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+4 and a subcarrier 12n+5 ofthe resource unit in frequency domain; and when a time-frequencyresource to which the third DMRS port group is mapped is the secondsymbol in time domain, the time-frequency resource includes at least oneof a subcarrier 12n+10 and a subcarrier 12n+11 of the resource unit infrequency domain.

When a time-frequency resource to which the fourth DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+6 and a subcarrier 12n+7 ofthe resource unit in frequency domain; and when a time-frequencyresource to which the fourth DMRS port group is mapped is the secondsymbol in time domain, the time-frequency resource includes at least oneof a subcarrier 12n and a subcarrier 12n+1 of the resource unit infrequency domain.

When a time-frequency resource to which the fifth DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+8 and a subcarrier 12n+9 ofthe resource unit in frequency domain; and when a time-frequencyresource to which the fifth DMRS port group is mapped is the secondsymbol in time domain, the time-frequency resource includes at least oneof a subcarrier 12n+2 and a subcarrier 12n+3 of the resource unit infrequency domain.

When a time-frequency resource to which the sixth DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+10 and a subcarrier 12n+11 ofthe resource unit in frequency domain; and when a time-frequencyresource to which the sixth DMRS port group is mapped is the secondsymbol in time domain, the time-frequency resource includes at least oneof a subcarrier 12n+4 and a subcarrier 12n+5 of the resource unit infrequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(b) in FIG. 23 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Third: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 6n of the resource unit in frequency domain; andwhen a time-frequency resource to which the first DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 6n+3 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 6n+1 of the resource unit in frequency domain; andwhen a time-frequency resource to which the second DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 6n+4 of the resource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 6n+2 of the resource unit in frequency domain; andwhen a time-frequency resource to which the third DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 6n+5 of the resource unit in frequency domain.

When a time-frequency resource to which the fourth DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 6n+3 of the resource unit in frequency domain; andwhen a time-frequency resource to which the fourth DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 6n of the resource unit in frequency domain.

When a time-frequency resource to which the fifth DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 6n+4 of the resource unit in frequency domain; andwhen a time-frequency resource to which the fifth DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 6n+1 of the resource unit in frequency domain.

When a time-frequency resource to which the sixth DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 6n+5 of the resource unit in frequency domain; andwhen a time-frequency resource to which the sixth DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 6n+2 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/6┘.

(c) in FIG. 23 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0 or 1.

Fourth: Time-frequency resources to which the first, second, and thirdDMRS port groups are mapped include the first symbol in time domain, andtime-frequency resources to which the fourth, fifth, and sixth DMRS portgroups are mapped include the second symbol in time domain.

When the time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n of the resource unit in frequency domain.

When the time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+1 of the resource unit in frequency domain.

When the time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+2 of the resource unit in frequency domain.

When the time-frequency resource to which the fourth DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n of the resource unit in frequency domain.

When the time-frequency resource to which the fifth DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+1 of the resource unit in frequency domain.

When the time-frequency resource to which the sixth DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+2 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/3┘.

(d) in FIG. 23 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, or 3. In this solution, the ports areevenly distributed in frequency domain and have a high density. Thisensures high channel estimation accuracy in various scenarios. Inaddition, the ports are evenly distributed but are mutually discrete infrequency domain. Therefore, this solution has a feature of a low PAPR,and is applicable to both a multi-carrier transmission scenario and asingle-carrier transmission scenario, thereby facilitating joint designof uplink and downlink transmission or multi-waveform transmission; andthis solution is applicable to an MU-MIMO scenario, thereby reducingDMRS indication overheads and design complexity of a system. In thissolution, each port is mapped to only one symbol. Therefore, phase noiseimpact is avoided, and this solution may be used in a high-frequencyscenario. In this solution, a quantity of symbols may be dynamicallyconfigured when quantities of ports are different. Therefore,flexibility is better, performance is ensured, and overheads arereduced. In addition, the ports are evenly mapped in frequency domain,thereby facilitating flexible scheduling.

(2) The 12 DMRS ports are divided into four DMRS port groups, and eachDMRS port group includes three DMRS ports. The four DMRS port groupsinclude a first DMRS port group, a second DMRS port group, a third DMRSport group, and a fourth DMRS port group. A same time-frequency resourceis multiplexed in a CDM manner for DMRSs corresponding to DMRS ports ineach DMRS port group. Mapping rules of the four DMRS port groups are asfollows:

First: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the solution corresponding to(a) in FIG. 20 . In this case, an example is shown in (a) in FIG. 24 .

Second: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, and asubcarrier 12n+2 of the resource unit in frequency domain; and when atime-frequency resource to which the first DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+6, a subcarrier 12n+7, and a subcarrier12n+8 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+3, a subcarrier 12n+4, and asubcarrier 12n+5 of the resource unit in frequency domain; and when atime-frequency resource to which the second DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+6, a subcarrier 12n+7, and asubcarrier 12n+8 of the resource unit in frequency domain; and when atime-frequency resource to which the third DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n, a subcarrier 12n+1, and a subcarrier12n+2 of the resource unit in frequency domain.

When a time-frequency resource to which the fourth DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain; and when atime-frequency resource to which the fourth DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+3, a subcarrier 12n+4, and a subcarrier12n+5 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(b) in FIG. 24 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Third: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol and the second symbol in time domain, thetime-frequency resource includes a subcarrier 4n of the resource unit infrequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol and the second symbol in time domain, thetime-frequency resource includes a subcarrier 4n+1 of the resource unitin frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol and the second symbol in time domain, thetime-frequency resource includes a subcarrier 4n+2 of the resource unitin frequency domain.

When a time-frequency resource to which the fourth DMRS port group ismapped is the first symbol and the second symbol in time domain, thetime-frequency resource includes a subcarrier 4n+3 of the resource unitin frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/4┘.

(c) in FIG. 24 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, or 2. In this solution, the ports areevenly distributed in frequency domain and distributed on the twosymbols, and have a high density. This ensures high channel estimationaccuracy in various scenarios. In addition, the ports are evenlydistributed but are mutually discrete in frequency domain. Therefore,this solution has a feature of a low PAPR, and is applicable to both amulti-carrier transmission scenario and a single-carrier transmissionscenario, thereby facilitating joint design of uplink and downlinktransmission or multi-waveform transmission; and this solution isapplicable to an MU-MIMO scenario, thereby reducing DMRS indicationoverheads and design complexity of a system. In addition, a port mappinglocation is fixed, and flexible port transmission is supported withoutchanging an original port mapping. Therefore, this solution is moregenerally used, and system indication overheads are reduced. Inaddition, the ports are evenly mapped in frequency domain, therebyfacilitating flexible scheduling. Further, power boosting or datatransmission may be performed at a location of an unoccupied port group.In addition, a CDM length in each port group is small, thereby ensuringbetter orthogonality between the ports.

Fourth: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 4n of the resource unit in frequency domain; andwhen a time-frequency resource to which the first DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 4n+2 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 4n+1 of the resource unit in frequency domain; andwhen a time-frequency resource to which the second DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 4n+3 of the resource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 4n+2 of the resource unit in frequency domain; andwhen a time-frequency resource to which the third DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 4n of the resource unit in frequency domain.

When a time-frequency resource to which the fourth DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 4n+3 of the resource unit in frequency domain; andwhen a time-frequency resource to which the fourth DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 4n+1 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/4┘.

(d) in FIG. 24 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, or 2.

Fifth: Time-frequency resources to which the first and second DMRS portgroups are mapped include the first symbol in time domain, andtime-frequency resources to which the third and fourth DMRS port groupsare mapped include the second symbol in time domain.

When the time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+2, a subcarrier 12n+6, a subcarrier 12n+7, and asubcarrier 12n+8 of the resource unit in frequency domain.

When the time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+3, a subcarrier 12n+4, asubcarrier 12n+5, a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain.

When the time-frequency resource to which the third DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+2, a subcarrier 12n+6, a subcarrier 12n+7, and asubcarrier 12n+8 of the resource unit in frequency domain.

When the time-frequency resource to which the fourth DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+3, a subcarrier 12n+4, asubcarrier 12n+5, a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(e) in FIG. 24 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

(3) The 12 DMRS ports are divided into three DMRS port groups, and eachDMRS port group includes four DMRS ports. The three DMRS port groupsinclude a first DMRS port group, a second DMRS port group, and a thirdDMRS port group. A same time-frequency resource is multiplexed in a CDMmanner for DMRSs corresponding to DMRS ports in each DMRS port group.Mapping rules of the three DMRS port groups are as follows:

First: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol and the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n, asubcarrier 12n+1, a subcarrier 12n+2, and a subcarrier 12n+3 of theresource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol and the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+4, asubcarrier 12n+5, a subcarrier 12n+6, and a subcarrier 12n+7 of theresource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol and the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+8, asubcarrier 12n+9, a subcarrier 12n+10, and a subcarrier 12n+11 of theresource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(a) in FIG. 25 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Second: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 12n, a subcarrier 12n+1, a subcarrier 12n+2, and asubcarrier 12n+3 of the resource unit in frequency domain; and when atime-frequency resource to which the first DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+8, a subcarrier 12n+9, a subcarrier12n+10, and a subcarrier 12n+11 of the resource unit in frequencydomain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 12n+4, a subcarrier 12n+5, a subcarrier 12n+6, anda subcarrier 12n+7 of the resource unit in frequency domain; and when atime-frequency resource to which the second DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n, a subcarrier 12n+1, a subcarrier12n+2, and a subcarrier 12n+3 of the resource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+8, a subcarrier 12n+9, asubcarrier 12n+10, and a subcarrier 12n+11 of the resource unit infrequency domain; and when a time-frequency resource to which the thirdDMRS port group is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+4, asubcarrier 12n+5, a subcarrier 12n+6, and a subcarrier 12n+7 of theresource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(b) in FIG. 25 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Third: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+2, and a subcarrier 12n+3 of the resource unit infrequency domain; and when a time-frequency resource to which the firstDMRS port group is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+4, asubcarrier 12n+5, a subcarrier 12n+6, and a subcarrier 12n+7 of theresource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+4, a subcarrier 12n+5, asubcarrier 12n+6, and a subcarrier 12n+7 of the resource unit infrequency domain; and when a time-frequency resource to which the secondDMRS port group is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+8, asubcarrier 12n+9, a subcarrier 12n+10, and a subcarrier 12n+11 of theresource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+8, a subcarrier 12n+9, asubcarrier 12n+10, and a subcarrier 12n+11 of the resource unit infrequency domain; and when a time-frequency resource to which the thirdDMRS port group is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n, asubcarrier 12n+1, a subcarrier 12n+2, and a subcarrier 12n+3 of theresource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(c) in FIG. 25 is a schematic diagram of a mapping rule of 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Fourth: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol.

When the time-frequency resource to which the first DMRS port group ismapped is the first symbol and the second symbol in time domain, thetime-frequency resource includes a subcarrier 3n of the resource unit infrequency domain.

When the time-frequency resource to which the second DMRS port group ismapped is the first symbol and the second symbol in time domain, thetime-frequency resource includes a subcarrier 3n+1 of the resource unitin frequency domain.

When the time-frequency resource to which the third DMRS port group ismapped is the first symbol and the second symbol in time domain, thetime-frequency resource includes a subcarrier 3n+2 of the resource unitin frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/3┘.

(d) in FIG. 25 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, or 3. In this solution, the ports areevenly distributed in frequency domain and distributed on the twosymbols, and have a high density. This ensures high channel estimationaccuracy in various scenarios. In addition, the ports are evenlydistributed but are mutually discrete in frequency domain. Therefore,this solution has a feature of a low PAPR, and is applicable to both amulti-carrier transmission scenario and a single-carrier transmissionscenario, thereby facilitating joint design of uplink and downlinktransmission or multi-waveform transmission; and this solution isapplicable to an MU-MIMO scenario, thereby reducing DMRS indicationoverheads and design complexity of a system. In addition, in thissolution, a port mapping location is fixed. Therefore, this solution ismore generally used, and system indication overheads are reduced. Inaddition, in this solution, the ports are evenly mapped in frequencydomain, thereby facilitating flexible scheduling. Further, powerboosting or data transmission may be performed at a location of anunoccupied port group.

Fifth: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n of the resource unit in frequency domain; andwhen a time-frequency resource to which the first DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+2 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+1 of the resource unit in frequency domain; andwhen a time-frequency resource to which the second DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n of the resource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+2 of the resource unit in frequency domain; andwhen a time-frequency resource to which the third DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+1 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/3┘.

(e) in FIG. 25 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, or 3.

Sixth: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n of the resource unit in frequency domain; andwhen a time-frequency resource to which the first DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+1 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+1 of the resource unit in frequency domain; andwhen a time-frequency resource to which the second DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+2 of the resource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 3n+2 of the resource unit in frequency domain; andwhen a time-frequency resource to which the third DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 3n of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/3┘.

(f) in FIG. 25 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, or 3.

Seventh: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+6, and a subcarrier 12n+7 of the resource unit infrequency domain; and when a time-frequency resource to which the firstDMRS port group is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+4, asubcarrier 12n+5, a subcarrier 12n+10, and a subcarrier 12n+11 of theresource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+2, a subcarrier 12n+3, asubcarrier 12n+8, and a subcarrier 12n+9 of the resource unit infrequency domain; and when a time-frequency resource to which the secondDMRS port group is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n, asubcarrier 12n+1, a subcarrier 12n+6, and a subcarrier 12n+7 of theresource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+4, a subcarrier 12n+5, asubcarrier 12n+10, and a subcarrier 12n+11 of the resource unit infrequency domain; and when a time-frequency resource to which the thirdDMRS port group is mapped is the second symbol in time domain, thetime-frequency resource includes at least one of a subcarrier 12n+2, asubcarrier 12n+3, a subcarrier 12n+8, and a subcarrier 12n+9 of theresource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(g) in FIG. 25 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

(4) The 12 DMRS ports are divided into two DMRS port groups, and eachDMRS port group includes six DMRS ports. The two DMRS port groupsinclude a first DMRS port group and a second DMRS port group. A sametime-frequency resource is multiplexed in a CDM manner for DMRSscorresponding to DMRS ports in each DMRS port group. Mapping rules ofthe two DMRS port groups are as follows:

First: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the solution corresponding to(a) in FIG. 21 . In this case, an example is shown in (a) in FIG. 26 .

Second: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the solution corresponding to(b) in FIG. 21 . In this case, an example is shown in (b) in FIG. 26 .

Third: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the solution corresponding to(c) in FIG. 21 . In this case, an example is shown in (c) in FIG. 26 .

Fourth: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the solution corresponding to(d) in FIG. 21 . In this case, an example is shown in (d) in FIG. 26 .

Fifth: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+2, a subcarrier 12n+3, a subcarrier 12n+4, and asubcarrier 12n+5 of the resource unit in frequency domain; and when atime-frequency resource to which the first DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+6, a subcarrier 12n+7, a subcarrier12n+8, a subcarrier 12n+9, a subcarrier 12n+10, and a subcarrier 12n+11of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+6, a subcarrier 12n+7, asubcarrier 12n+8, a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain; and when atime-frequency resource to which the second DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n, a subcarrier 12n+1, a subcarrier12n+2, a subcarrier 12n+3, a subcarrier 12n+4, and a subcarrier 12n+5 ofthe resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(a) in FIG. 27 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Sixth: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+2, a subcarrier 12n+6, a subcarrier 12n+7, and asubcarrier 12n+8 of the resource unit in frequency domain; and when atime-frequency resource to which the first DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+3, a subcarrier 12n+4, a subcarrier12n+5, a subcarrier 12n+9, a subcarrier 12n+10, and a subcarrier 12n+11of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+3, a subcarrier 12n+4, asubcarrier 12n+5, a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain; and when atime-frequency resource to which the second DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n, a subcarrier 12n+1, a subcarrier12n+2, a subcarrier 12n+6, a subcarrier 12n+7, and a subcarrier 12n+8 ofthe resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(b) in FIG. 27 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Seventh: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+4, a subcarrier 12n+5, a subcarrier 12n+8, and asubcarrier 12n+9 of the resource unit in frequency domain; and when atime-frequency resource to which the first DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+2, a subcarrier 12n+3, a subcarrier12n+6, a subcarrier 12n+7, a subcarrier 12n+10, and a subcarrier 12n+11of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+2, a subcarrier 12n+3, asubcarrier 12n+6, a subcarrier 12n+7, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain; and when atime-frequency resource to which the second DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n, a subcarrier 12n+1, a subcarrier12n+4, a subcarrier 12n+5, a subcarrier 12n+8, and a subcarrier 12n+9 ofthe resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(c) in FIG. 27 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Eighth: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 2n of the resource unit in frequency domain; andwhen a time-frequency resource to which the first DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 2n+1 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 2n+1 of the resource unit in frequency domain; andwhen a time-frequency resource to which the second DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 2n of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/2┘.

(d) in FIG. 27 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, 3, 4, or 5.

Ninth: A time-frequency resource to which the first DMRS port group ismapped includes the first symbol in time domain, and a time-frequencyresource to which the second DMRS port group is mapped includes thesecond symbol in time domain.

When the time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceis a subcarrier 2n of the resource unit in frequency domain.

When the time-frequency resource to which the second DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceis a subcarrier 2n of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/2┘.

(e) in FIG. 27 is a schematic diagram of a mapping rule of the 12 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, 3, 4, or 5. Each small blank blockindicates an RE to which a DMRS port group is not mapped.

(4) A same time-frequency resource is multiplexed in a CDM manner forDMRSs corresponding to the 12 DMRS ports. In this case, the 12 DMRSports may be considered as one DMRS port group. Mapping rules of theDMRS port group are as follows:

When the time-frequency resource to which the DMRS port group is mappedis the first symbol and the second symbol in time domain, thetime-frequency resource includes a subcarrier n of the resource unit infrequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan M.

FIG. 28 is a schematic diagram of a mapping rule of the 12 DMRS ports.Each small shaded block indicates an RE to which a DMRS port group ismapped, and n=0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11.

A total quantity of system-supported DMRS ports is 16.

1. Time-frequency resources to which the 16 DMRS ports are mappedinclude a first symbol of a resource unit in time domain.

(1) The 16 DMRS ports are divided into four DMRS port groups, and eachDMRS port group includes four DMRS ports. The four DMRS port groupsinclude a first DMRS port group, a second DMRS port group, a third DMRSport group, and a fourth DMRS port group. A same time-frequency resourceis multiplexed in a CDM manner for DMRSs corresponding to DMRS ports ineach DMRS port group. Mapping rules of the four DMRS port groups are asfollows:

First:

A time-frequency resource to which the first DMRS port group is mappedincludes at least one of a subcarrier 12n, a subcarrier 12n+1, and asubcarrier 12n+2 of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes at least one of a subcarrier 12n+3, a subcarrier 12n+4, and asubcarrier 12n+5 of the resource unit in frequency domain.

A time-frequency resource to which the third DMRS port group is mappedincludes at least one of a subcarrier 12n+6, a subcarrier 12n+7, and asubcarrier 12n+8 of the resource unit in frequency domain.

A time-frequency resource to which the fourth DMRS port group is mappedincludes at least one of a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(a) in FIG. 29 is a schematic diagram of a mapping rule of the 16 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Second:

A time-frequency resource to which the first DMRS port group is mappedincludes a subcarrier 4n of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes a subcarrier 4n+1 of the resource unit in frequency domain.

A time-frequency resource to which the third DMRS port group is mappedincludes a subcarrier 4n+2 of the resource unit in frequency domain.

A time-frequency resource to which the fourth DMRS port group is mappedincludes a subcarrier 4n+3 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/4┘.

(b) in FIG. 29 is a schematic diagram of a mapping rule of the 16 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, or 2.

(2) The 16 DMRS ports are divided into two DMRS port groups, and eachDMRS port group includes eight DMRS ports. The two DMRS port groupsinclude a first DMRS port group and a second DMRS port group. A sametime-frequency resource is multiplexed in a CDM manner for DMRSscorresponding to DMRS ports in each DMRS port group. Mapping rules ofthe two DMRS port groups are as follows:

First:

A time-frequency resource to which the first DMRS port group is mappedincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+4, a subcarrier 12n+5, a subcarrier 12n+8, and asubcarrier 12n+9 of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes at least one of a subcarrier 12n+2, a subcarrier 12n+3, asubcarrier 12n+6, a subcarrier 12n+7, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency) domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(a) in FIG. 30 is a schematic diagram of a mapping rule of the 16 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Second:

A time-frequency resource to which the first DMRS port group is mappedincludes a subcarrier 2n of the resource unit in frequency domain.

A time-frequency resource to which the second DMRS port group is mappedincludes a subcarrier 2n+1 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/2┘.

(b) in FIG. 30 is a schematic diagram of a mapping rule of the 16 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, 3, 4, or 5.

(3) A same time-frequency resource is multiplexed in a CDM manner forDMRSs corresponding to the 16 DMRS ports. In this case, the 16 DMRSports may be considered as one DMRS port group. Mapping rules of theDMRS port group are as follows:

A time-frequency resource to which the DMRS port group is mappedincludes a subcarrier n of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan M.

FIG. 31 is a schematic diagram of a mapping rule of the 16 DMRS ports.Each small shaded block indicates an RE to which a DMRS port group ismapped, and n=0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11.

2. Time-frequency resources to which the 16 DMRS ports are mappedinclude a first symbol and a second symbol of a resource unit in timedomain.

(1) The 16 DMRS ports are divided into four DMRS port groups, and eachDMRS port group includes four DMRS ports. The four DMRS port groupsinclude a first DMRS port group, a second DMRS port group, a third DMRSport group, and a fourth DMRS port group. A same time-frequency resourceis multiplexed in a CDM manner for DMRSs corresponding to DMRS ports ineach DMRS port group. Mapping rules of the four DMRS port groups are asfollows:

First: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the solution corresponding to(a) in FIG. 29 . In this case, an example is shown in (a) in FIG. 32 .

Second: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the solution corresponding to(b) in FIG. 29 . In this case, an example is shown in (b) in FIG. 32 .In this solution, the ports are evenly distributed in frequency domainand distributed on the two symbols, and have a high density. Thisensures high channel estimation accuracy in various scenarios. Inaddition, the ports are evenly distributed but are mutually discrete infrequency domain. Therefore, this solution has a feature of a low PAPR,and is applicable to both a multi-carrier transmission scenario and asingle-carrier transmission scenario, thereby implementing joint designof uplink and downlink transmission or multi-waveform transmission; andthis solution is applicable to an MU-MIMO scenario, thereby reducingDMRS indication overheads and design complexity of a system. Inaddition, in this solution, a port mapping location is fixed. Therefore,this solution is more generally used, and system indication overheadsare reduced. In this solution, the ports are evenly mapped in frequencydomain, thereby facilitating flexible scheduling. Further, powerboosting or data transmission may be performed at a location of anunoccupied port group.

Third: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, and asubcarrier 12n+2 of the resource unit in frequency domain; and when atime-frequency resource to which the first DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+6, a subcarrier 12n+7, and a subcarrier12n+8 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+3, a subcarrier 12n+4, and asubcarrier 12n+5 of the resource unit in frequency domain; and when atime-frequency resource to which the second DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+6, a subcarrier 12n+7, and asubcarrier 12n+8 of the resource unit in frequency domain; and when atime-frequency resource to which the third DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n, a subcarrier 12n+1, and a subcarrier12n+2 of the resource unit in frequency domain.

When a time-frequency resource to which the fourth DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+9, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain; and when atime-frequency resource to which the fourth DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+3, a subcarrier 12n+4, and a subcarrier12n+5 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(c) in FIG. 32 is a schematic diagram of a mapping rule of the 16 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Fourth: Time-frequency resources to which the first and second DMRS portgroups are mapped include the first symbol in time domain, andtime-frequency resources to which the third and fourth DMRS port groupsare mapped include the second symbol in time domain.

When the time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceis at least one of a subcarrier 12n, a subcarrier 12n+1, a subcarrier12n+2, a subcarrier 12n+6, a subcarrier 12n+7, and a subcarrier 12n+8 ofthe resource unit in frequency domain.

When the time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceis at least one of a subcarrier 12n+3, a subcarrier 12n+4, a subcarrier12n+5, a subcarrier 12n+9, a subcarrier 12n+10, and a subcarrier 12n+11of the resource unit in frequency domain.

When the time-frequency resource to which the third DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceis at least one of a subcarrier 12n, a subcarrier 12n+1, a subcarrier12n+2, a subcarrier 12n+6, a subcarrier 12n+7, and a subcarrier 12n+8 ofthe resource unit in frequency domain.

When the time-frequency resource to which the fourth DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceis at least one of a subcarrier 12n+3, a subcarrier 12n+4, a subcarrier12n+5, a subcarrier 12n+9, a subcarrier 12n+10, and a subcarrier 12n+11of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(d) in FIG. 32 is a schematic diagram of a mapping rule of the 16 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Fifth: Time-frequency resources to which the first and second DMRS portgroups are mapped include the first symbol in time domain, andtime-frequency resources to which the third and fourth DMRS port groupsare mapped include the second symbol in time domain.

When the time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceis at least one of a subcarrier 12n, a subcarrier 12n+1, a subcarrier12n+4, a subcarrier 12n+5, a subcarrier 12n+8, and a subcarrier 12n+9 ofthe resource unit in frequency domain.

When the time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceis at least one of a subcarrier 12n+2, a subcarrier 12n+3, a subcarrier12n+6, a subcarrier 12n+7, a subcarrier 12n+10, and a subcarrier 12n+11of the resource unit in frequency domain.

When the time-frequency resource to which the third DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceis at least one of a subcarrier 12n, a subcarrier 12n+1, a subcarrier12n+4, a subcarrier 12n+5, a subcarrier 12n+8, and a subcarrier 12n+9 ofthe resource unit in frequency domain.

When the time-frequency resource to which the fourth DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceis at least one of a subcarrier 12n+2, a subcarrier 12n+3, a subcarrier12n+6, a subcarrier 12n+7, a subcarrier 12n+10, and a subcarrier 12n+11of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(e) in FIG. 32 is a schematic diagram of a mapping rule of the 16 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Sixth: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 4n of the resource unit in frequency domain; andwhen a time-frequency resource to which the first DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 4n+2 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 4n+1 of the resource unit in frequency domain; andwhen a time-frequency resource to which the second DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 4n+3 of the resource unit in frequency domain.

When a time-frequency resource to which the third DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 4n+2 of the resource unit in frequency domain; andwhen a time-frequency resource to which the third DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 4n of the resource unit in frequency domain.

When a time-frequency resource to which the fourth DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 4n+3 of the resource unit in frequency domain; andwhen a time-frequency resource to which the fourth DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 4n+1 of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/4┘.

(f) in FIG. 32 is a schematic diagram of a mapping rule of the 16 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, or 2.

(2) The 16 DMRS ports are divided into two DMRS port groups, and eachDMRS port group includes eight DMRS ports. The two DMRS port groupsinclude a first DMRS port group and a second DMRS port group. A sametime-frequency resource is multiplexed in a CDM manner for DMRSscorresponding to DMRS ports in each DMRS port group. Mapping rules ofthe two DMRS port groups are as follows:

First: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the solution corresponding to(a) in FIG. 30 . In this case, an example is shown in (a) in FIG. 33 .

Second: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol; and for thetime-frequency resource to which each DMRS port group is mapped infrequency domain, reference may be made to the solution corresponding to(b) in FIG. 30 . In this case, an example is shown in (b) in FIG. 33 .In this solution, the ports are evenly distributed in frequency domainand distributed on the two symbols, and have a high density. Thisensures high channel estimation accuracy in various scenarios. Inaddition, the ports are evenly distributed but are mutually discrete infrequency domain. Therefore, this solution has a feature of a low PAPR,and is applicable to both a multi-carrier transmission scenario and asingle-carrier transmission scenario, thereby facilitating joint designof uplink and downlink transmission or multi-waveform transmission; andthis solution is applicable to an MU-MIMO scenario, thereby reducingDMRS indication overheads and design complexity of a system. Inaddition, in this solution, a port mapping location is fixed. Therefore,this solution is more generally used, and system indication overheadsare reduced. In this solution, the ports are evenly mapped in frequencydomain, thereby facilitating flexible scheduling. Further, powerboosting or data transmission may be performed at a location of anunoccupied port group.

Third: A time-frequency resource to which each DMRS port group is mappedincludes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n, a subcarrier 12n+1, asubcarrier 12n+4, a subcarrier 12n+5, a subcarrier 12n+8, and asubcarrier 12n+9 of the resource unit in frequency domain; and when atime-frequency resource to which the first DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n+2, a subcarrier 12n+3, a subcarrier12n+6, a subcarrier 12n+7, a subcarrier 12n+10, and a subcarrier 12n+11of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes at least one of a subcarrier 12n+2, a subcarrier 12n+3, asubcarrier 12n+6, a subcarrier 12n+7, a subcarrier 12n+10, and asubcarrier 12n+11 of the resource unit in frequency domain; and when atime-frequency resource to which the second DMRS port group is mapped isthe second symbol in time domain, the time-frequency resource includesat least one of a subcarrier 12n, a subcarrier 12n+1, a subcarrier12n+4, a subcarrier 12n+5, a subcarrier 12n+8, and a subcarrier 12n+9 ofthe resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/12┘.

(c) in FIG. 33 is a schematic diagram of a mapping rule of the 16 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0.

Fourth: A time-frequency resource to which each DMRS port group ismapped includes the first symbol and the second symbol.

When a time-frequency resource to which the first DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 2n of the resource unit in frequency domain; andwhen a time-frequency resource to which the first DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 2n+1 of the resource unit in frequency domain.

When a time-frequency resource to which the second DMRS port group ismapped is the first symbol in time domain, the time-frequency resourceincludes a subcarrier 2n+1 of the resource unit in frequency domain; andwhen a time-frequency resource to which the second DMRS port group ismapped is the second symbol in time domain, the time-frequency resourceincludes a subcarrier 2n of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan └M/2┘.

(d) in FIG. 33 is a schematic diagram of a mapping rule of the 16 DMRSports. Each small shaded block indicates an RE to which a DMRS portgroup is mapped, and n=0, 1, 2, 3, 4, or 5.

(3) A same time-frequency resource is multiplexed in a CDM manner forDMRSs corresponding to the 16 DMRS ports. In this case, the 16 DMRSports may be considered as one DMRS port group. Mapping rules of theDMRS port group are as follows:

A time-frequency resource to which the DMRS port group is mappedincludes a subcarrier n of the resource unit in frequency domain.

n may be any one or more integers greater than or equal to 0 and lessthan M.

FIG. 34 is a schematic diagram of a mapping rule of the 16 DMRS ports.Each small shaded block indicates an RE to which a DMRS port group ismapped, and n=0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, or 11.

The foregoing mainly describes, from a perspective of interactionbetween network elements, the solutions provided in the embodiments ofthis application. It can be understood that the network elements may be,for example, base stations or terminals. To implement the foregoingfunctions, the network elements include corresponding hardwarestructures and/or software modules for performing the functions. Aperson skilled in the art should be easily aware that in combinationwith the examples described in the embodiments disclosed in thisspecification, units and algorithm steps may be implemented by hardwareor a combination of hardware and computer software in this application.Whether a function is performed by hardware or hardware driven bycomputer software depends on particular applications and designconstraints of the technical solutions. A person skilled in the art mayuse different methods to implement the described functions for eachparticular application, but it should not be considered that theimplementation goes beyond the scope of this application.

In the embodiments of this application, division of function modules maybe performed on the base station or the terminal based on the foregoingmethod examples. For example, the function modules may be divided basedon the corresponding functions, or two or more functions may beintegrated into one processing module. The integrated module may beimplemented in a form of hardware, or may be implemented in a form of asoftware function module. It should be noted that the module division inthe embodiments of this application is an example and is merely logicalfunction division. During actual implementation, there may be otherdivision manners. The following provides descriptions by using examplesin which function modules are divided based on corresponding functions.

FIG. 35 is a schematic structural diagram of an apparatus 350 forsending a DMRS. The apparatus 350 may be the base station 100 or theterminal 200. The apparatus 350 may include a determining unit 3501 anda sending unit 3502. The determining unit 3501 may be configured toperform FIG. 6 and/or other processes used to support the technologiesdescribed in this specification. The sending unit 3502 may be configuredto perform an action performed by the transmit end in S102 in FIG. 6and/or other processes used to support the technologies described inthis specification. All related content of the steps in the foregoingmethod embodiments may be used for describing functions of thecorresponding function modules, and therefore details are not describedherein again.

FIG. 36 is a schematic structural diagram of an apparatus 360 forobtaining a DMRS. The apparatus 360 may include a determining unit 3601,an obtaining unit 3602, and a receiving unit 3603. The apparatus 360 maybe the terminal 200 or the base station 100. The determining unit 3601may be configured to perform S103 in FIG. 6 and/or other processes usedto support the technologies described in this specification. Theobtaining unit 3602 may be configured to perform S104 in FIG. 6 and/orother processes used to support the technologies described in thisspecification. The receiving unit 3603 is configured to perform anaction performed by the receive end in S102 in FIG. 6 . All relatedcontent of the steps in the foregoing method embodiments may be used fordescribing functions of the corresponding function modules, andtherefore details are not described herein again. For example, in aspecific implementation process, it can be understood that the apparatus360 first obtains, through, for example, but not limited to, inverseFourier transform (IFFT), a symbol carried on each RE (for example,obtains a symbol carried on each subcarrier and in each OFDM symbol),and then obtains a DMRS from the obtained symbol based on atime-frequency resource on which the DMRS is located.

FIG. 37 is a schematic structural diagram of an indication apparatus.The apparatus 370 may be the base station 100. The apparatus 370 mayinclude a generation unit 3701 and a sending unit 3702. The generationunit 3701 may be configured to perform S201 in FIG. 6 a and/or otherprocesses used to support the technologies described in thisspecification. The sending unit 3702 may be configured to perform anaction performed by the base station in S202 in FIG. 6 a and/or otherprocesses used to support the technologies described in thisspecification. All related content of the steps in the foregoing methodembodiments may be used for describing functions of the correspondingfunction modules, and therefore details are not described herein again.

FIG. 38 is a schematic structural diagram of an apparatus 380 fordetermining a time-frequency resource. The apparatus 380 may include areceiving unit 3801 and a determining unit 3802. The apparatus 380 maybe the base station 100. The receiving unit 3801 is configured toperform an action performed by the receive end in S202 in FIG. 6 aand/or other processes used to support the technologies described inthis specification. The determining unit 3802 may be configured toperform S203 in FIG. 6 a and/or other processes used to support thetechnologies described in this specification. All related content of thesteps in the foregoing method embodiments may be used for describingfunctions of the corresponding function modules, and therefore detailsare not described herein again.

In embodiments of this application, the apparatus 350 to the apparatus380 are presented in a form of dividing the function modules based onthe corresponding functions, or are presented in a form of dividing thefunction modules in an integrated manner. The “modules” herein may be anapplication-specific integrated circuit (ASIC), a processor thatexecutes one or more software or firmware programs and a memory, anintegrated logic circuit, and/or another device capable of providing theforegoing functions, where the processor and the memory may beintegrated together or independent of each other.

In a simple embodiment, a person skilled in the art may figure out thatany one of the apparatus 350 to the apparatus 380 is implemented by astructure shown in FIG. 39 .

As shown in FIG. 39 , an apparatus 390 may include a memory 3902, aprocessor 3901, and a communications interface 3903. The memory 3902 isconfigured to store a computer executable instruction. When theapparatus 390 runs, the processor 3901 executes the computer executableinstruction stored in the memory 3902, so that the apparatus 390performs an information transmission method provided in an embodiment ofthis application. For a specific information transmission method, referto related descriptions in the foregoing and the accompanying drawings.Details are not described herein again. The communications interface3903 may be a transceiver.

Optionally, the apparatus 390 may be a field-programmable gate array(FPGA), an application-specific integrated chip (ASIC), a system on chip(SoC), a central processing unit (CPU), a network processor (NP), adigital signal processing circuit (DSP), or a micro controller (MCU), ormay be a programmable controller (PLD) or another integrated chip.

An embodiment of this application further provides a storage medium. Thestorage medium may include the memory 3902.

An information transmission apparatus provided in an embodiment of thisapplication may be configured to perform the information transmissionmethod. Therefore, for a technical effect that can be achieved by theinformation transmission apparatus, refer to the foregoing methodembodiments. Details are not described again in this embodiment of thisapplication.

All or some of the foregoing embodiments may be implemented by usingsoftware, hardware, firmware, or any combination thereof. When asoftware program is used to implement the embodiments, all or some ofthe embodiments may be implemented in a form of a computer programproduct. The computer program product includes one or more computerinstructions. When the computer program instructions are loaded andexecuted on a computer, all or some of the procedures or functionsdescribed in the embodiments of this application are generated. Thecomputer may be a general-purpose computer, a special-purpose computer,a computer network, or another programmable apparatus. The computerinstructions may be stored in a computer-readable storage medium or maybe transmitted from a computer-readable storage medium to anothercomputer-readable storage medium. For example, the computer instructionsmay be transmitted from a website, computer, server, or data center toanother website, computer, server, or data center in a wired (forexample, a coaxial cable, an optical fiber, or a digital subscriber line(DSL)) or wireless (for example, infrared, radio, or microwave) manner.The computer-readable storage medium may be any usable medium that canbe accessed by a computer, or a data storage device, such as a server ora data center, integrating one or more usable media. The usable mediummay be a magnetic medium (for example, a floppy disk, a hard disk, or amagnetic tape), an optical medium (for example, a DVD), a semiconductormedium (for example, a solid state disk (SSD)), or the like.

Although this application is described with reference to theembodiments, in a process of implementing this application that claimsprotection, a person skilled in the art may understand and implementother variations of the disclosed embodiments by viewing theaccompanying drawings, the disclosed content, and the accompanyingclaims. In the claims, “comprising” does not exclude other component orother steps, and “a” or “one” does not exclude a case of “a pluralityof”. A single processor or other units may implement several functionsenumerated in the claims. Some measures are recorded in dependent claimsthat are different from each other, but this does not mean that thesemeasures cannot be combined to produce a better effect.

Although this application is described with reference to specificfeatures and the embodiments thereof, apparently, various modificationsand combinations may be made to them without departing from the spiritand scope of this application. Correspondingly, this specification andthe accompanying drawings are merely example descriptions of thisapplication defined by the accompanying claims, and are considered asany of or all modifications, variations, combinations or equivalentsthat cover the scope of this application. Apparently, a person skilledin the art can make various modifications and variations to thisapplication without departing from the spirit and scope of thisapplication. In this way, this application is intended to cover thesemodifications and variations of this application, provided that thesemodifications and variations fall within the scope defined by the claimsof this application and equivalent technologies thereof

What is claimed is:
 1. A method for sending a demodulation referencesignal (DMRS), comprising: determining a time-frequency resource used tocarry the DMRS, wherein the DMRS is carried on the time-frequencyresource in at least one resource unit, wherein a total quantity ofsupported DMRS ports is six DMRS ports, the six DMRS ports are dividedinto three DMRS port groups, each DMRS port group comprises two DMRSports, the three DMRS port groups comprise a first DMRS port group, asecond DMRS port group, and a third DMRS port group, and a sametime-frequency resource is multiplexed for the DMRS ports in each DMRSport group in a code division multiplexing (CDM) manner, wherein, ineach resource unit, a time-frequency resource to which the first DMRSport group is mapped comprises a subcarrier 0, a subcarrier 1, asubcarrier 6, and a subcarrier 7 that are in a first symbol and a secondsymbol in a time domain, a time-frequency resource to which the secondDMRS port group is mapped comprises a subcarrier 2, a subcarrier 3, asubcarrier 8, and a subcarrier 9 that are in the first symbol and thesecond symbol in the time domain, and a time-frequency resource to whichthe third DMRS port group is mapped comprises a subcarrier 4, asubcarrier 5, a subcarrier 10, and a subcarrier 11 that are in the firstsymbol and the second symbol in the time domain; and sending the DMRS byusing the time-frequency resource.
 2. The method according to claim 1,wherein the resource unit is a resource block (RB).
 3. The methodaccording to claim 1, wherein the first symbol and the second symbol arecontinuous in the time domain.
 4. The method according to claim 1,wherein the DMRS is a DMRS for a downlink transmission or a DMRS for anuplink transmission.
 5. A method for obtaining a demodulation referencesignal (DMRS), comprising: determining a time-frequency resource used tocarry the DMRS, wherein the DMRS is carried on the time-frequencyresource in at least one resource unit, wherein a total quantity ofsupported DMRS ports is six DMRS ports, the six DMRS ports are dividedinto three DMRS port groups, each DMRS port group comprises two DMRSports, the three DMRS port groups comprise a first DMRS port group, asecond DMRS port group, and a third DMRS port group, and a sametime-frequency resource is multiplexed for the DMRS ports in each DMRSport group in a code division multiplexing (CDM) manner, wherein, ineach resource unit, a time-frequency resource to which the first DMRSport group is mapped comprises a subcarrier 0, a subcarrier 1, asubcarrier 6, and a subcarrier 7 that are in a first symbol and a secondsymbol in a time domain, a time-frequency resource to which the secondDMRS port group is mapped comprises a subcarrier 2, a subcarrier 3, asubcarrier 8, and a subcarrier 9 that are in the first symbol and thesecond symbol in the time domain, and a time-frequency resource to whichthe third DMRS port group is mapped comprises a subcarrier 4, asubcarrier 5, a subcarrier 10, and a subcarrier 11 that are in the firstsymbol and the second symbol in the time domain; and obtaining the DMRSby using the time-frequency resource.
 6. The method according to claim5, wherein the resource unit is a resource block (RB).
 7. The methodaccording to claim 5, wherein the first symbol and the second symbol arecontinuous in the time domain.
 8. The method according to claim 5,wherein the DMRS is a DMRS for a downlink transmission or a DMRS for anuplink transmission.
 9. An indication method, comprising: generatingindication information, wherein the indication information is used toindicate a time-frequency resource used to carry a demodulationreference signal (DMRS), wherein the DMRS is carried on thetime-frequency resource in at least one resource unit, wherein a totalquantity of supported DMRS ports is six DMRS ports, the six DMRS portsare divided into three DMRS port groups, each DMRS port group comprisestwo DMRS ports, the three DMRS port groups comprise a first DMRS portgroup, a second DMRS port group, and a third DMRS port group, and a sametime-frequency resource is multiplexed for the DMRS ports in each DMRSport group in a code division multiplexing (CDM) manner, wherein, ineach resource unit, a time-frequency resource to which the first DMRSport group is mapped comprises a subcarrier 0, a subcarrier 1, asubcarrier 6, and a subcarrier 7 that are in a first symbol and a secondsymbol in a time domain, a time-frequency resource to which the secondDMRS port group is mapped comprises a subcarrier 2, a subcarrier 3, asubcarrier 8, and a subcarrier 9 that are in the first symbol and thesecond symbol in the time domain, and a time-frequency resource to whichthe third DMRS port group is mapped comprises a subcarrier 4, asubcarrier 5, a subcarrier 10, and a subcarrier 11 that are in the firstsymbol and the second symbol in the time domain; and sending theindication information.
 10. The method according to claim 9, wherein theresource unit is a resource block (RB).
 11. The method according toclaim 9, wherein the first symbol and the second symbol are continuousin the time domain.
 12. The method according to claim 9, wherein theDMRS is a DMRS for a downlink transmission or a DMRS for an uplinktransmission.
 13. A method for determining a time-frequency resource,comprising: receiving indication information, wherein the indicationinformation is used to indicate a time-frequency resource used to carrya demodulation reference signal (DMRS), wherein the DMRS is carried onthe time-frequency resource in at least one resource unit, wherein atotal quantity of supported DMRS ports is six DMRS ports, the six DMRSports are divided into three DMRS port groups, each DMRS port groupcomprises two DMRS ports, the three DMRS port groups comprise a firstDMRS port group, a second DMRS port group, and a third DMRS port group,and a same time-frequency resource is multiplexed for the DMRS ports ineach DMRS port group in a code division multiplexing (CDM) manner,wherein, in each resource unit, a time-frequency resource to which thefirst DMRS port group is mapped comprises a subcarrier 0, a subcarrier1, a subcarrier 6, and a subcarrier 7 that are in a first symbol and asecond symbol in a time domain, a time-frequency resource to which thesecond DMRS port group is mapped comprises a subcarrier 2, a subcarrier3, a subcarrier 8, and a subcarrier 9 that are in the first symbol andthe second symbol in the time domain, and a time-frequency resource towhich the third DMRS port group is mapped comprises a subcarrier 4, asubcarrier 5, a subcarrier 10, and a subcarrier 11 that are in the firstsymbol and the second symbol in the time domain; and determining thetime-frequency resource based on the indication information.
 14. Themethod according to claim 13, wherein the resource unit is a resourceblock (RB).
 15. The method according to claim 13, wherein the firstsymbol and the second symbol are continuous in the time domain.
 16. Themethod according to claim 13, wherein the DMRS is a DMRS for a downlinktransmission or a DMRS for an uplink transmission.
 17. An apparatus forsending a demodulation reference signal (DMRS), comprising: at least oneprocessor, and one or more memories coupled to the at least oneprocessor and storing computer instructions for execution by the atleast one processor to configure the apparatus for: determining atime-frequency resource used to carry the DMRS, wherein the DMRS iscarried on the time-frequency resource in at least one resource unit,wherein a total quantity of supported DMRS ports is six DMRS ports, thesix DMRS ports are divided into three DMRS port groups, each DMRS portgroup comprises two DMRS ports, the three DMRS port groups comprise afirst DMRS port group, a second DMRS port group, and a third DMRS portgroup, and a same time-frequency resource is multiplexed for the DMRSports in each DMRS port group in a code division multiplexing (CDM)manner, wherein, in each resource unit, a time-frequency resource towhich the first DMRS port group is mapped comprises a subcarrier 0, asubcarrier 1, a subcarrier 6, and a subcarrier 7 that are in a firstsymbol and a second symbol in a time domain, a time-frequency resourceto which the second DMRS port group is mapped comprises a subcarrier 2,a subcarrier 3, a subcarrier 8, and a subcarrier 9 that are in the firstsymbol and the second symbol in the time domain, and a time-frequencyresource to which the third DMRS port group is mapped comprises asubcarrier 4, a subcarrier 5, a subcarrier 10, and a subcarrier 11 thatare in the first symbol and the second symbol in the time domain; andsending the DMRS by using the time-frequency resource.
 18. The apparatusaccording to claim 17, wherein the resource unit is a resource block(RB).
 19. The apparatus according to claim 17, wherein the first symboland the second symbol are continuous in the time domain.
 20. Theapparatus according to claim 17, wherein the DMRS is a DMRS for adownlink transmission or a DMRS for an uplink transmission.
 21. Anapparatus for obtaining a demodulation reference signal (DMRS),comprising: at least one processor, and one or more memories coupled tothe at least one processor and storing computer instructions forexecution by the at least one processor to configure the apparatus for:determining a time-frequency resource used to carry the DMRS, whereinthe DMRS is carried on the time-frequency resource in at least oneresource unit, wherein a total quantity of supported DMRS ports is sixDMRS ports, the six DMRS ports are divided into three DMRS port groups,each DMRS port group comprises two DMRS ports, the three DMRS portgroups comprise a first DMRS port group, a second DMRS port group, and athird DMRS port group, and a same time-frequency resource is multiplexedfor the DMRS ports in each DMRS port group in a code divisionmultiplexing (CDM) manner, wherein, in each resource unit, atime-frequency resource to which the first DMRS port group is mappedcomprises a subcarrier 0, a subcarrier 1, a subcarrier 6, and asubcarrier 7 that are in a first symbol and a second symbol in a timedomain, a time-frequency resource to which the second DMRS port group ismapped comprises a subcarrier 2, a subcarrier 3, a subcarrier 8, and asubcarrier 9 that are in the first symbol and the second symbol in thetime domain, and a time-frequency resource to which the third DMRS portgroup is mapped comprises a subcarrier 4, a subcarrier 5, a subcarrier10, and a subcarrier 11 that are in the first symbol and the secondsymbol in the time domain; and obtaining the DMRS by using thetime-frequency resource.
 22. The apparatus according to claim 21,wherein the resource unit is a resource block (RB).
 23. The apparatusaccording to claim 21, wherein the first symbol and the second symbolare continuous in the time domain.
 24. The apparatus according to claim21, wherein the DMRS is a DMRS for a downlink transmission or a DMRS foran uplink transmission.
 25. An indication apparatus, comprising: atleast one processor, and one or more memories coupled to the at leastone processor and storing computer instructions for execution by the atleast one processor to configure the apparatus for: generatingindication information, wherein the indication information is used toindicate a time-frequency resource used to carry a demodulationreference signal (DMRS), wherein the DMRS is carried on thetime-frequency resource in at least one resource unit, wherein a totalquantity of supported DMRS ports is six DMRS ports, the six DMRS portsare divided into three DMRS port groups, each DMRS port group comprisestwo DMRS ports, the three DMRS port groups comprise a first DMRS portgroup, a second DMRS port group, and a third DMRS port group, and a sametime-frequency resource is multiplexed for the DMRS ports in each DMRSport group in a code division multiplexing (CDM) manner, wherein, ineach resource unit, a time-frequency resource to which the first DMRSport group is mapped comprises a subcarrier 0, a subcarrier 1, asubcarrier 6, and a subcarrier 7 that are in a first symbol and a secondsymbol in a time domain, a time-frequency resource to which the secondDMRS port group is mapped comprises a subcarrier 2, a subcarrier 3, asubcarrier 8, and a subcarrier 9 that are in the first symbol and thesecond symbol in the time domain, and a time-frequency resource to whichthe third DMRS port group is mapped comprises a subcarrier 4, asubcarrier 5, a subcarrier 10, and a subcarrier 11 that are in the firstsymbol and the second symbol in the time domain; and sending theindication information.
 26. The apparatus according to claim 25, whereinthe resource unit is a resource block (RB).
 27. The apparatus accordingto claim 25, wherein the first symbol and the second symbol arecontinuous in the time domain.
 28. The apparatus according to claim 25,wherein the DMRS is a DMRS for a downlink transmission or a DMRS for anuplink transmission.
 29. An apparatus for determining a time-frequencyresource, comprising: at least one processor, and one or more memoriescoupled to the at least one processor and storing computer instructionsfor execution by the at least one processor to configure the apparatusfor: receiving indication information, wherein the indicationinformation is used to indicate a time-frequency resource used to carrya demodulation reference signal (DMRS), wherein the DMRS is carried onthe time-frequency resource in at least one resource unit, wherein atotal quantity of supported DMRS ports is six DMRS ports, the six DMRSports are divided into three DMRS port groups, each DMRS port groupcomprises two DMRS ports, the three DMRS port groups comprise a firstDMRS port group, a second DMRS port group, and a third DMRS port group,and a same time-frequency resource is multiplexed for the DMRS ports ineach DMRS port group in a code division multiplexing (CDM) manner,wherein, in each resource unit, a time-frequency resource to which thefirst DMRS port group is mapped comprises a subcarrier 0, a subcarrier1, a subcarrier 6, and a subcarrier 7 that are in a first symbol and asecond symbol in a time domain, a time-frequency resource to which thesecond DMRS port group is mapped comprises a subcarrier 2, a subcarrier3, a subcarrier 8, and a subcarrier 9 that are in the first symbol andthe second symbol in the time domain, and a time-frequency resource towhich the third DMRS port group is mapped comprises a subcarrier 4, asubcarrier 5, a subcarrier 10, and a subcarrier 11 that are in the firstsymbol and the second symbol in the time domain; and determining thetime-frequency resource based on the indication information.
 30. Theapparatus according to claim 29, wherein the resource unit is a resourceblock (RB).
 31. The apparatus according to claim 29, wherein the firstsymbol and the second symbol are continuous in the time domain.
 32. Theapparatus according to claim 29, wherein the DMRS is a DMRS for adownlink transmission or a DMRS for an uplink transmission.
 33. Anon-transitory computer-readable storage medium, wherein thenon-transitory computer-readable storage medium stores computerinstructions, and when the computer instructions run on a computer, thecomputer performs steps comprising: determining a time-frequencyresource used to carry a demodulation reference signal (DMRS), whereinthe DMRS is carried on the time-frequency resource in at least oneresource unit, wherein a total quantity of supported DMRS ports is sixDMRS ports, the six DMRS ports are divided into three DMRS port groups,each DMRS port group comprises two DMRS ports, the three DMRS portgroups comprise a first DMRS port group, a second DMRS port group, and athird DMRS port group, and a same time-frequency resource is multiplexedfor the DMRS ports in each DMRS port group in a code divisionmultiplexing (CDM) manner, wherein, in each resource unit, atime-frequency resource to which the first DMRS port group is mappedcomprises a subcarrier 0, a subcarrier 1, a subcarrier 6, and asubcarrier 7 that are in a first symbol and a second symbol in a timedomain, a time-frequency resource to which the second DMRS port group ismapped comprises a subcarrier 2, a subcarrier 3, a subcarrier 8, and asubcarrier 9 that are in the first symbol and the second symbol in thetime domain, and a time-frequency resource to which the third DMRS portgroup is mapped comprises a subcarrier 4, a subcarrier 5, a subcarrier10, and a subcarrier 11 that are in the first symbol and the secondsymbol in the time domain; and sending the DMRS by using thetime-frequency resource.
 34. The non-transitory computer storage mediumaccording to claim 33, wherein the resource unit is a resource block(RB).
 35. The non-transitory computer storage medium according to claim33, wherein the first symbol and the second symbol are continuous in thetime domain.
 36. The non-transitory computer storage medium according toclaim 33, wherein the DMRS is a DMRS for a downlink transmission or aDMRS for an uplink transmission.
 37. A non-transitory computer-readablestorage medium, wherein the non-transitory computer-readable storagemedium stores computer instructions, and when the computer instructionsrun on a computer, the computer performs steps comprising: determining atime-frequency resource used to carry a demodulation reference signal(DMRS), wherein the DMRS is carried on the time-frequency resource in atleast one resource unit, wherein a total quantity of supported DMRSports is six DMRS ports, the six DMRS ports are divided into three DMRSport groups, each DMRS port group comprises two DMRS ports, the threeDMRS port groups comprise a first DMRS port group, a second DMRS portgroup, and a third DMRS port group, and a same time-frequency resourceis multiplexed for the DMRS ports in each DMRS port group in a codedivision multiplexing (CDM) manner, wherein, in each resource unit, atime-frequency resource to which the first DMRS port group is mappedcomprises a subcarrier 0, a subcarrier 1, a subcarrier 6, and asubcarrier 7 that are in a first symbol and a second symbol in a timedomain, a time-frequency resource to which the second DMRS port group ismapped comprises a subcarrier 2, a subcarrier 3, a subcarrier 8, and asubcarrier 9 that are in the first symbol and the second symbol in thetime domain, and a time-frequency resource to which the third DMRS portgroup is mapped comprises a subcarrier 4, a subcarrier 5, a subcarrier10, and a subcarrier 11 that are in the first symbol and the secondsymbol in the time domain; and obtaining the DMRS by using thetime-frequency resource.
 38. The non-transitory computer storage mediumaccording to claim 37, wherein the resource unit is a resource block(RB).
 39. The non-transitory computer storage medium according to claim37, wherein the first symbol and the second symbol are continuous in thetime domain.
 40. The non-transitory computer storage medium according toclaim 37, wherein the DMRS is a DMRS for a downlink transmission or aDMRS for an uplink transmission.
 41. A non-transitory computer-readablestorage medium, wherein the non-transitory computer-readable storagemedium stores computer instructions, and when the computer instructionsrun on a computer, the computer performs steps comprising: generatingindication information, wherein the indication information is used toindicate a time-frequency resource used to carry a demodulationreference signal (DMRS), wherein the DMRS is carried on thetime-frequency resource in at least one resource unit, wherein a totalquantity of supported DMRS ports is six DMRS ports, the six DMRS portsare divided into three DMRS port groups, each DMRS port group comprisestwo DMRS ports, the three DMRS port groups comprise a first DMRS portgroup, a second DMRS port group, and a third DMRS port group, and a sametime-frequency resource is multiplexed for the DMRS ports in each DMRSport group in a code division multiplexing (CDM) manner, wherein, ineach resource unit, a time-frequency resource to which the first DMRSport group is mapped comprises a subcarrier 0, a subcarrier 1, asubcarrier 6, and a subcarrier 7 that are in a first symbol and a secondsymbol in a time domain, a time-frequency resource to which the secondDMRS port group is mapped comprises a subcarrier 2, a subcarrier 3, asubcarrier 8, and a subcarrier 9 that are in the first symbol and thesecond symbol in the time domain, and a time-frequency resource to whichthe third DMRS port group is mapped comprises a subcarrier 4, asubcarrier 5, a subcarrier 10, and a subcarrier 11 that are in the firstsymbol and the second symbol in the time domain; and sending theindication information.
 42. The non-transitory computer storage mediumaccording to claim 33, wherein the resource unit is a resource block(RB).
 43. The non-transitory computer storage medium according to claim33, wherein the first symbol and the second symbol are continuous in thetime domain.
 44. The non-transitory computer storage medium according toclaim 33, wherein the DMRS is a DMRS for a downlink transmission or aDMRS for an uplink transmission.
 45. A non-transitory computer-readablestorage medium, wherein the computer-readable storage medium storescomputer instructions, and when the computer instructions run on acomputer, the computer performs steps comprising: receiving indicationinformation, wherein the indication information is used to indicate atime-frequency resource used to carry a demodulation reference signal(DMRS), wherein the DMRS is carried on the time-frequency resource in atleast one resource unit, wherein a total quantity of supported DMRSports is six DMRS ports, the six DMRS ports are divided into three DMRSport groups, each DMRS port group comprises two DMRS ports, the threeDMRS port groups comprise a first DMRS port group, a second DMRS portgroup, and a third DMRS port group, and a same time-frequency resourceis multiplexed for the DMRS ports in each DMRS port group in a codedivision multiplexing (CDM) manner, wherein, in each resource unit, atime-frequency resource to which the first DMRS port group is mappedcomprises a subcarrier 0, a subcarrier 1, a subcarrier 6, and asubcarrier 7 that are in a first symbol and a second symbol in a timedomain, a time-frequency resource to which the second DMRS port group ismapped comprises a subcarrier 2, a subcarrier 3, a subcarrier 8, and asubcarrier 9 that are in the first symbol and the second symbol in thetime domain, and a time-frequency resource to which the third DMRS portgroup is mapped comprises a subcarrier 4, a subcarrier 5, a subcarrier10, and a subcarrier 11 that are in the first symbol and the secondsymbol in the time domain; and determining the time-frequency resourcebased on the indication information.
 46. The non-transitory computerstorage medium according to claim 45, wherein the resource unit is aresource block (RB).
 47. The non-transitory computer storage mediumaccording to claim 45, wherein the first symbol and the second symbolare continuous in the time domain.
 48. The non-transitory computerstorage medium according to claim 45, wherein the DMRS is a DMRS for adownlink transmission or a DMRS for an uplink transmission.